Updated Hypertension Guidelines Released by ACP, AAFP
Saturday 11, 2017
The American College of Physicians (ACP) and the American Academy of Family Physicians (AAFP) have released a joint practice guideline on systolic blood pressure targets for people aged 60 years and older with hypertension. The guidance calls for physicians to start treatment for patients who have persistent systolic blood pressure at or above 150 mm Hg to achieve a target of less than 150 mm Hg to reduce risk for stroke, cardiac events, and death. The recommendation was rated strong, with high-quality evidence. "The evidence showed that any additional benefit from aggressive blood pressure control is small, with a lower magnitude of benefit and inconsistent results across outcomes," ACP's President Nitin S. Damle, MD, said in a news release. However, in some cases, a lower systolic target should be considered, according to the guidelines.
If patients have a history of stroke or transient ischemic attack or have high cardiovascular risk, physicians should consider starting or increasing drug therapy to achieve systolic blood pressure of less than 140 mm Hg to reduce risk for stroke and cardiac events. The authors note, however, that this recommendation was rated weak, with moderate-quality evidence. High cardiovascular risk generally includes patients with diabetes, vascular disease, metabolic syndrome, or chronic kidney disease, as well as older adults. The guidelines also emphasize that cost burden for patients should be considered in any treatment discussions. "When prescribing drug therapy, clinicians should select generic formulations over brand-name drugs, which have similar efficacy, reduced cost, and therefore better adherence," they write. In addition, the guidelines stress that clinicians should periodically discuss the potential benefits and harms of specific blood pressure targets with the patient. The full guidelines, written by Amir Qaseem, MD, PhD, head of the ACP guidelines committee, and colleagues, were published online January 17 in the Annals of Internal Medicine. A guideline summary will be published in the March/April 2017 issue of the Annals of Family Medicine.
Lower Targets Also Have Risks
In a supporting evidence review, Jessica Weiss, MD, MCR, from the Portland Veterans Affairs Medical Center in Oregon, and colleagues warn that the benefits of a lower threshold (less than 140/90) should be weighed against risk. "Tighter control may prevent, on average, roughly 10 to 20 events for every 1000 high-risk patients treated over 5 years across a population," they write. But the trade-off may be higher costs and greater risk for hypotension and syncope. "On the other hand, we found that lower targets are unlikely to increase the risk for dementia, fractures, and falls or reduce quality of life," Dr Weiss and colleagues write. Most of the support for treatment targets below 140 mm Hg come from a single trial that had a target of less than 120 mm Hg, the reviewers note. The Systolic Blood Pressure Intervention Trial (SPRINT), as previously reported by heartwire from Medscape, compared benefit of a systolic target of less than 120 mm Hg vs less than 140 mm Hg and found substantial reductions in cardiac events and deaths with tighter control. However, the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, which tested the same targets, did not show similar benefits.
When you remove SPRINT data from the analysis, the effects on mortality were reduced and the effects on cardiovascular events were no longer significant, Dr Weiss and colleagues write. The guidelines mention "white coat" syndrome, which can skew blood pressure readings. Before changing any treatment plan, the authors urge physicians to ensure they are getting the most accurate numbers over time. ACP and AAFP did not have enough evidence to make recommendations regarding diastolic blood pressure targets.
Substantial Improvements in Morbidity Possible
In an accompanying editorial, Michael Pignone, MD, MPH, from the Department of Medicine, University of Texas Dell Medical School in Austin, and Anthony J. Viera MD, MPH, from the Department of Family Medicine, University of North Carolina in Chapel Hill, write that improving blood pressure control in this patient group has the potential to substantially reduce morbidity and mortality. They note that 65% of US adults aged 60 years and older have hypertension, and only about half (52.5%) have controlled blood pressure levels (defined as less than 140/90 mm Hg). "Over 15% of persons with hypertension are unaware of their condition," they write.
With the publication of the new ACP/AAFP guidelines, they say physicians who want to implement high-value prevention programs should take the following steps:
- offer accurate blood pressure measurement taken by a well-trained staff and offer training in home or ambulatory monitoring;
- routinely assess CVD risk in patients older than 40 years and in some younger patients with prominent risk factors;
- train providers in shared decision making for the treatment of high blood pressure;
- create a registry to track hypertensive patients; and
- use additional nonvisit follow-up measures for patients with moderate to severe hypertension.
"Such programs, when implemented, have been associated with large improvements in blood pressure control and have the potential to significantly reduce hypertension-related morbidity and mortality, particularly in older adults," the editorialists write.
Near-death experiences: Fact or fantasy?
Tuesday 7, 2016
Suddenly amidst all this pain I saw a light very faint and in the distance. It got nearer to me, and everything was so quiet; it was warm, I was warm, and all the pain began to go [...] I was finally there, and I felt as if someone had put their arms around me. I was safe, no more pain, nothing, just this lovely, caring sensation."
The quote above comes from a 48-year-old woman who, on one occasion, almost died from complications related to a spinal tumor; it evokes much of the general emotion associated with a classic near-death experience story.
The term "near-death experience" (NDE) is well-known throughout America, but the phenomenon is not restricted solely to the Western world. Most cultures have an equivalent experience; even children have related NDEs.
An NDE might involve walking toward a bright light at the end of a tunnel, meeting gods, speaking with relatives who are long-dead, out-of-body experiences (OBEs) or feeling bathed in light.
Almost unanimously a significant life experience, conversations about NDEs are often accompanied by discussions of the afterlife and the mind surviving the mortal body.
These kinds of esoteric tales would normally be banished to the realms of pseudoscience and parapsychology, but their pervasive nature - an estimated 3 percent of Americans report having experienced an NDE - has sparked a smattering of genuine scientific research and a wealth of conjecture.
What do NDEs consist of?
One Dutch study, published in The Lancet, set out to investigate the regularity of NDEs and tried to tease apart causal factors.
The investigators reported that 50 percent of individuals who experienced an NDE mentioned an awareness of being dead, 56 percent regarded it a positive experience, 24 percent reported an OBE, 31 percent described traveling through a tunnel and 32 percent spoke of interacting with deceased people.
The study also showed that, of the patients they interviewed, although all were clinically dead at one point, only a small percentage (18 percent) experienced, or remembered, the NDE. The likelihood of having an NDE was not related to the level of cerebral anoxia (lack of oxygen to the brain), the amount of preceding fear or the type of medication they were taking.
According to the paper, NDEs were more often experienced by patients under 60, and women more commonly described deeper experiences. Conversely, those with memory deficits following resuscitation were less likely to report NDEs, which is to be expected.
There is obviously something driving these experiences, but the factors that impact them are still very much up for debate.
Cultural flexibility in NDEs
The NDE phenomenon is particularly fascinating because the psychological and physiological factors are intimately tied to social and cultural factors. For instance, the NDE of a 40-year-old white male from Nebraska might include visions of a shimmering white, bearded male beckoning him through pearl-encrusted gates; the NDE of a 12-year-old boy from Papa New Guinea probably will not.
The Mapuche people of South America and residents of Hawaii are more likely to see landscapes and volcanoes, whereas NDEs in Thailand and India rarely involve landmarks, tunnels or light; for Tibetans, light features more heavily, as do illusions of reincarnation.
The following narrative comes from an African NDE, reported in 1992. A young man had been attacked by a lioness after attempting to capture one of her cubs:
"I could see myself going into some kind of a trance. A highway suddenly opened up before me. It seemed to be going endlessly into the sky. Along it were a lot of stars, also spreading up to the sky.
Each time I tried to get on the highway, the stars would block my way. I just stood there not knowing what to do. After a while, the highway and stars disappeared. I woke
up and found myself in a hospital bed."
Europeans and North Americans often visualize beautiful gardens; intriguingly, the Kalai of Melanesia are more inclined to see an industrialized world of factories.
Culture and a person's hopes or dreams clearly influence the nature of NDEs; but what biological mechanisms could be behind this strange phenomenon?
What is behind NDEs?
A phenomenon so widely experienced cannot be dismissed as just another old wives' tale, there has to be something biological at work to explain its prevalence.
Some observers claim that NDEs display a rift in current neuroscientific theory, and that the experience shows another, more esoteric facet to our existence.
Many believe we should split the mind from the functions of the brain, once and for all.
However, this type of thinking is not necessary to explain NDEs; rather than claiming paranormal origins, the field of cognitive neuroscience has attacked the problem as it would any other: as an output of the brain.
There are a few potential explanations, any number of which might be involved in each individual's experience. The following are some attempts to explain the biological origin of NDEs.
The role of expectation
Expectation surely plays a part in the overall NDE; the differences between cultures mentioned above are testament to that. But expectation seems to play an even deeper role.
Interestingly, NDEs sometimes occur in people who were, in reality, nowhere near death, they just thought they were. One study that included 58 patients' experiences of NDEs found that 30 were not, in fact, close to dying. However, there is more to an NDE than expectations, as we shall see.
OBEs are commonly a part of NDEs and sometimes include autoscopy - seeing one's body from above. Although this seems like an otherworldly event, neuroscientists know that OBEs also happen in settings other than the near-deathbed.
For instance, during an attack of sleep paralysis, which affects up to 40 percent of people at some point in their lives, OBEs are common. Sleep paralysis occurs when an individual is still essentially in REM sleep, but their brain awakens partially.
During REM sleep, the brain effectively paralyzes the body to prevent it from acting out dreams. The brain, still believing that the person is asleep, keeps this lock on the body, subjecting the individual to a terrifying, literal, waking nightmare. The experience often involves a sensation of floating from one's body and viewing the room from the ceiling's perspective.
Other researchers have demonstrated that by stimulating the right temporoparietal junction (TPJ), they could induce OBEs artificially. The TPJ is a section of the brain that collates information from the thalamus (regulator of consciousness, sleep, and alertness), limbic system (involved in emotion, behavior, motivation, and long-term memory), and the senses.
So, regardless of how real the autoscopy feels, it can still be explained in neuroscientific terms.
Meeting the dead
Meeting and greeting the dead is another commonly reported aspect of NDEs and can be partially explained away by expectations. Cultures are often filled to the brim with tales of heaven or some other type of afterlife where long-dead relatives eagerly await us.
Added to this, people with Alzheimer's and Parkinson's are known to have vivid hallucinations of ghost-like entities; some report seeing dead relatives in their homes. These types of apparitions have been linked to pallidotomy lesions - a kind of neurosurgery used in some Parkinson's patients.
The experiences are considered to be due to dysfunction in the pathways of dopamine, a neurotransmitter involved in the brain's reward pathways that is known to cause hallucinations.
In truth, it is surprising that we do not hallucinate more than we already do. Our brains weave our senses into the experience of perception in such a way that we forget what a difficult and amazing job they do.
Any cracks in the perceptual sphere are seamlessly back-filled by the brain; as a quick example, we all have a blind spot where the optic nerve meets the retina. In this section of our visual field, we can see nothing at all, but we never notice because our brain simply fills in the blanks.
But on occasion, if under duress or when receiving confusing inputs, rather than penciling in a chair, a patch of wallpaper, or a door, it fills the void with a goblin or ghoul.
In macular degeneration, the center of the visual field gradually fails; patients report the hallucination of ghosts relatively frequently. This might be due to the brain attempting to make sense of the neural "noise" being generated from the faulty or partial messages it is receiving.
In short, a brain hallucinating at a time when it is receiving unusual signals, or not receiving appropriate signals, is not such a surprise.
Explaining the euphoria
Often, NDEs are reported as a euphoric, blissful experience. At first glance, this seems paradoxical, given the circumstances surrounding NDEs. However, a number of recreational drugs have been found to closely mimic the visual and emotional aspects of NDEs.
One such drug - ketamine - that is used both recreationally and as an anesthetic, can produce hallucinations, OBEs, euphoria, dissociation, and spiritual experiences. Ketamine produces these effects by acting at N-methyl-D-aspartate (NMDA) receptors, the same receptors utilized by other recreational drugs, such as amphetamines.
When an animal is under extreme stress, dopamine and opioid pathways are known to trigger. These reward pathways seem to come into play during traumatic events; although we do not know exactly why this should be, they no doubt evolved to be of assistance in times of extreme danger.
A brain in shock, being flooded by natural opioids, can go some of the way to explaining the intense feelings of quiet and calm.
The tunnel of light
Possibly the most well-known facet of an NDE is the feeling of being drawn into a long tunnel with a bright light at the end. Some researchers believe that this phenomenon can be explained by retinal ischemia (lack of oxygen to the retina).
The theory goes that, as the retina is starved of oxygen, peripheral vision slowly decays and only the center of the visual field can be seen. Tunnel vision is a symptom of both extreme fear and oxygen loss (hypoxia), both of which are often present during the process of dying.
No doubt, NDEs are a complex phenomenon with a myriad of mechanisms behind them. From a lack of oxygen affecting the visual system to a brain struggling to make sense of strange emotions; from the drug-like triggering of reward pathways and a host of cultural expectations. Being close to death (or believing that you are) is a unique physiological and psychological experience. It is little wonder that it produces such a confusion of sights and sounds.
The precise nature of each NDE will not be unraveled for many years. After all, catching them in action, at one of the most critical points of an individual's life is no easy task, and the ethics of experimental interventions could prove tricky.
One thing is for sure, NDEs are fascinating and are (probably) nothing to do with the afterlife.
Written by Tim Newman
Muscle growth may be improved with longer rest between weightlifting sets
Monday 9, 2016
Muscle growth may be improved with longer rest between weightlifting sets
Contrary to popular belief, a new study suggests taking longer breaks between sets of weightlifting may promote muscle growth.
The research reveals that men who had longer rest periods between four weightlifting sets showed a significant increase in muscle rebuilding activity - a process that aids muscle growth - compared with those who had shorter rest periods. Study co-author Dr. Leigh Breen, from the University of Birmingham in the United Kingdom, and colleagues recently published their findings in the journal Experimental Physiology. Weightlifting is a form of resistance exercise that involves lifting weights as a way to boost muscle size and strength. According to the Centers for Disease Control and Prevention (CDC), adults should engage in moderate- or high-intensity muscle-strengthening activities - such as weightlifting - at least 2 days each week, and these activities should incorporate all major muscle groups. Such activity is recommended in addition to either 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity aerobic activity, in order to reap extra health benefits. To get the most from weightlifting and other muscle-strengthening exercises, it is recommended that such activities are performed in sets. For example, the CDC suggest performing 8-12 repetitions of lifting a weight in two or three sets to gain extra benefits. But how long should the rest period be between each set?
Extended rest periods increased myofibrillar protein synthesis
It is widely accepted that an individual should take time to rest between weightlifting sets in order to give the muscles time to recover, but popular notion holds that the shorter the rest time, the greater the muscle growth. However, the new study from Dr. Breen and colleagues suggests this may not be the case. To reach their findings, the researchers enrolled 16 men and asked them to complete four sets of weightlifting in the form of a bilateral leg press and knee extension exercise. The men were asked to rest for either 1 minute or 5 minutes between each set. The researchers took muscle biopsies from the men as soon as all four sets were completed, as well as 4, 24, and 28 hours after. The biopsies were analyzed to establish levels of myofibrillar protein synthesis (MPS) - the process by which damaged proteins within muscle cells are rebuilt, aiding muscle growth - and intracellular signaling.
Within the first 4 hours after exercise, the team found that the men who had the longer 5-minute rest period between each weightlifting set showed a greater increase in MPS, at 156 percent, compared with those who had the shorter 1-minute rest period, who saw a 76 percent increase in MPS.
Based on their results, the researchers suggest that shorter rest periods between weightlifting sets may actually hinder the muscle growth process.
"With short rests of 1 minute, though the hormonal response is superior, the actual muscle response is blunted.
If you're looking for maximized muscle growth with your training program, a slightly longer interval between sets may provide a better chance of having the muscle response you're looking for."
Dr. Leigh Breen
Rest periods should last at least 2-3 minutes
The researchers recommend that weightlifting novices should take rest periods of at least 2-3 minutes between sets. "Over time, they may need to find ways to push beyond the plateau of muscle-building that commonly occurs, and so may gradually decrease their rest periods," notes Dr. Breen. For the more experienced weightlifter, Dr. Breen says it is possible that shorter rest periods may not have such a negative impact on the muscle-building process, particularly if their body has adapted to such stress. "Nonetheless, similar recommendations of 2-3 minutes between sets should help to ensure maximal muscle growth in well-trained individuals," she adds. The researchers are now planning to conduct a follow-up study to assess the longer-term impact of extended rest periods between weightlifting sets on muscle growth.
Written by Honor Whiteman
Warfarin use for atrial fibrillation increases dementia risk
Friday 6, 2016
Warfarin use for atrial fibrillation increases dementia risk
Atrial fibrillation is a relatively common condition, and - because of the aging population - it is becoming more common. This rise is mirrored by elevated usage of the blood-thinning drug, warfarin. The drug has saved countless lives, but new research shows a hidden danger - an increased risk of dementia in atrial fibrillation patients.
Warfarin has been used to prevent potentially life-threatening blood clots for more than half a century; an estimated 20 million Americans are currently taking the drug. Atrial fibrillation (AF) refers to an irregular, often abnormally fast, heartbeat. It can cause a range of symptoms, including shortness of breath, dizziness, and tiredness. There are an estimated 2.7 million Americans living with AF. According to the American Heart Association, AF increases the risk of stroke fivefold. For this reason, warfarin's ability to prevent blood clots is a potential life-saver. Because blood clots can seriously affect brain function, AF is known to enhance the risk of developing dementia. On the other hand, blood thinners used to ease AF symptoms increase the likelihood of brain bleeds that can, over time, have a negative impact on brain function.
Warfarin and dementia
Warfarin has been used for many years and is prescribed in large quantities across the industrialized world. New research, presented at the Heart Rhythm Society's 37th Annual Scientific Sessions, used data from more than 10,000 patients to investigate links between warfarin, dementia, and AF. Each of the participants in the study was a long-term user of warfarin. Some used the drug for AF, others used it for different conditions including thromboembolism and valvular heart disease. None had a history of dementia. After 7 years, the group was followed up. The team found that dementia was more prevalent in the AF group than the non-AF group, 5.8 percent compared with 1.6 percent, respectively. The study was conducted by Dr. T. Jared Bunch and a team of researchers at Intermountain Medical Center Heart Institute in Salt Lake City, UT. They showed that individuals using warfarin for AF on a long-term basis had increased rates of vascular dementia and Alzheimer's when compared with warfarin users with conditions other than AF.
The trouble with warfarin
Warfarin is a notoriously challenging drug to administer at the correct levels. A tightrope has to be walked between the risks of clotting on one side and bleeding on the other. Each patient responds differently to warfarin, and multiple factors can impact the drug's effects. Additionally, its actions in the body take time to develop, so finding the right dosage can be a long process. These factors combined make warfarin levels difficult to manage. Previous research demonstrated that worse warfarin management might increase the chances of developing dementia in AF patients. The current research backed up these earlier findings; the risk was indeed heightened in patients whose dosage was more difficult to manage. However, they also found that, independent of the quality of warfarin management, dementia levels still increased. In short, the researchers showed that whether warfarin levels were too high, too low, or at the right dosage, the risk of dementia still increased.
"Our study results are the first to show that there are significant cognitive risk factors for patients treated with Warfarin over a long period of time regardless of the indication for anticoagulation."
T. Jared Bunch, MD
Future concerns surrounding warfarin
For a number of reasons, Dr. Bunch believes that these results are of great importance. Firstly, it is important to know about any risks associated with a medication, especially one that is used so commonly. He recommends that only people who absolutely need blood thinners should be prescribed them. Secondly, the results suggest that other medications that can increase the chances of bleeding, like aspirin, should be avoided by individuals taking blood thinners, unless entirely necessary. Also, for those who are taking warfarin, but whose dosage levels are difficult to manage, switching to newer, more predictable drugs might be a safer solution. Because of warfarin's widespread usage, the findings of any research into its associated risks are likely to spark debate.
Written by Tim Newman
In Cancer Screening, Why Not Tell the Truth?
January 21, 2016
In Cancer Screening, Why Not Tell the Truth?
An unpleasant emotion caused by the belief that something is dangerous. This is fear. This is cancer. The motivation to screen for cancer, therefore, is easy to understand. The problem: cancer screening has not worked. Recent reviews of the evidence show that current-day screening techniques do not save lives. Worse, in many cases, these good-intentioned searches bring harm to previously healthy people. I realize this sounds shocking. It did to me, too. Millions of women and men have had their breasts squished, veins poked, lungs irradiated, and bowels invaded in the name of "health" maintenance. I've been scolded for forgoing PSA tests and colonoscopy — "you should know better, John." I know what you may be thinking. We have all heard the anecdotes — cases that are often celebrated in local news reports and hospital marketing material. People saved by early detection, and the opposite: the unscreened felled by late-stage disease. Anecdotes, however compelling, are not evidence. When you pull up a chair, open your computer, take a breath, suspend past beliefs, and look for the evidence that screening saves lives, it simply isn't there. One reason that this many people (doctors and patients alike) have been misled about screening has been our collective attachment to the belief that if screening lowers disease-specific death rates, that would translate to lower overall mortality. That is: breast, lung, and colon cancer are bad diseases, so it makes sense that lowering death from those three types of cancer would extend life.
It is not so.
Facts, Not Fear
In a comprehensive review of the literature published in the BMJ, Drs Vinay Prasad (Oregon Health Sciences University, Portland) and David Newman (School of Medicine at Mount Sinai, New York), along with journalist Jeanne Lenzer, find that disease-specific mortality is a lousy surrogate for overall mortality. They report that when a screening technique does lower disease-specific death rates, which is both uncommon and of modest degree, there are no differences in overall mortality.
The authors cite three reasons why cancer screening might not reduce overall mortality:
- Screening trials were underpowered to detect differences. I'm no statistician, but doesn't the fact that a trial requires millions of subjects to show a difference, mean there is little, if any, difference?
- "Downstream effects of screening may negate any disease-specific gains." My translation: harm. Dr Peter Gøtzsche (Nordic Cochrane Center, Copenhagen) wrote in a commentary that "screening always causes harm. Sometimes it also leads to benefits, and sometimes these benefits outweigh the harms." To understand harm resulting from screening, one need only to consider that a prostate biopsy entails sticking a needle through the rectum, or that some drugs used to treat breast cancer damage the heart.
- Screening might not reduce overall mortality because of "off-target deaths." An illustration of this point is provided by a cohort study that found a possible increased risk of suicide and cardiovascular death in men in the year after being diagnosed with prostate cancer. People die — of all sorts of causes, not just cancer.
Let's also be clear that this one paper is not an outlier. A group of Stanford researchers performed a systematic review and meta-analyses of randomized trials of screening tests for 19 diseases (39 tests) where mortality is a common outcome. They found reductions in disease-specific mortality were uncommon and reductions in overall mortality were rare or nonexistent. Drs Archie Bleyer and H Gilbert Welch (St Charles Health System, Central Oregon, Portland) reviewed Surveillance, Epidemiology, and End Results (SEER) data from 1976 through 2008 and concluded that "screening mammography has only marginally reduced the rate at which women present with advanced cancer and that overdiagnosis may account for nearly a third of all new breast cancer cases." Likewise, a Cochrane Database Systematic review of eight trials and 600,000 women did not find an effect of screening on either breast cancer mortality or all-cause mortality. This evidence caused the Swiss medical board to abolish screening mammography. These are the data. It's now clear to me that mass cancer screening does not save lives. But I'm still trying to understand how this practice became entrenched as public-health gospel. It has to be more than fear.
How We Say It Matters
Dr Gerd Gigerenzer (Max Planck Institute, Berlin, Germany) offered a clue in his editorial accompanying the recently published literature review and analysis by Prasad and colleagues. He pointed to language and the ability of words to persuade. Instead of saying "early detection," advocates might use the term "prevention." This, Dr Gigerenzer says, wrongly suggests screening reduces the odds of getting cancer. Doesn't looking for cancer increase the odds of getting the diagnosis of cancer?
Gigerenzer noted two other ways language is used to emphasize screening benefits over harms:
- The reporting of benefits in relative, not absolute terms.
- The equating of increases in 5-year survival rates with decreases in mortality.
I would add to this list of word misuse, the practice of referring to women sent to mammography screening as patients. They are not patients; they are well people. Dr Gigerenzer agreed with the commonsense notion that overall mortality should be reported along with cancer-specific mortality. His editorial included a fact box on breast cancer early detection using mammography provided by the Harding Center for Risk Literacy. I challenge you to tell me why such text boxes should not be shown to people before they undergo screening,
Fixing a Public-Health Problem
Given these revelations, I conclude that we have a massive public-health problem. Any expert in problem solving will tell you the first step of getting out of hole is to stop digging. I see three obvious next steps:
The first action healthcare experts should take is to spread the word that there is nothing about the mass screening of healthy people for cancer that equates to health maintenance. Embrace clear language. Saying or implying that screening saves lives when there are no data to support it and lots to refute it undermines trust in the medical profession.
The second action healthcare experts should take is to stop wasting money on screening. If the evidence shows no difference in overall mortality, why pay for it? I'm not naive to the fact that use of clear language will decrease the number of billable procedures. I am not saying this will be easy. One first move that would be less painful would be to get rid of quality measures or incentives that promote screening.
I want to be clear; I'm not saying all cancer screening is worthless. People at higher baseline risk for cancer, such as those with a family history of cancer or environmental exposures, might derive more benefit than harm from screening. Prasad, Lenzer, and Newman say this group of patients would be a good place to spend future research dollars. That sounds reasonable. I also acknowledge that some people, even when presented with the evidence, will want to proceed with screening. We can argue about who should pay for non–evidence-based medical procedures.
The most important action that all of us (patients, nurses, doctors, and healthcare writers) should take is to learn from this revelation. There's nothing bad about the fact that current-day screening tests don't save lives. Cancer is a tough disease, and in some ways, it may be the natural order of cell biology. What's bad about this medical reversal has been our blindness to the evidence.
We let what we believe become what we know. In clinical medicine, that should be a never event.
Written by John M Mandrola, MD
Stress: its surprising implications for health
January 14, 2016
Stress: its surprising implications for health
Whether it is down to work pressure, money worries or relationship troubles, most of us experience stress at some point in our lives. In fact, around 75% of us report experiencing moderate to high levels of stress over the past month. It is well known that stress can cause sleep problems, headache and raise the risk of depression. But in this Spotlight, we look at some of the more surprising ways in which stress may harm our health.
The National Institute of Mental Health (NIMH) define stress as the "brain's response to any demand." In other words, it is how the brain reacts to certain situations or events.
It is important to note that not all stress is negative. Many of us who have been in a pressurized situation may have found that stress has pushed us to perform better. This is down to a "fight-or-flight" response, whereby the brain identifies a real threat and quickly releases hormones that encourage us to protect ourselves from perceived harm.
It is when this fight-or-flight response overreacts that problems arise, and this usually happens when we find ourselves exposed to constant threats.
"Stress is caused by the loss or threat of loss of the personal, social and material resources that are primary to us. So, threat to self, threat to self-esteem, threat to income, threat to employment and threat to our family or our health," Stevan Hobfoll, PhD, the Judd and Marjorie Weinberg presidential professor and chair at Rush University Medical Center in Chicago, IL, and member of the American Psychological Association (APA), told Medical News Today.
Stress levels 'too high' in Americans
In February last year, the APA released their annual "Stress in America" Survey, which assesses the attitudes and perceptions of stress and identifies its primary causes among the general public.
The survey, completed by 3,068 adults in the US during August 2014, revealed that the primary cause of stress among Americans is money, with 72% of respondents reporting feeling stressed about finances at some point over the past month. Of these, 22% said they had felt "extreme stress" in the past month as a result of money worries.
The second most common cause of stress among Americans was found to be work, followed by the economy, family responsibilities and personal health concerns.
On a positive note, average stress levels among Americans have decreased since 2007. On a 10-point scale, respondents rated their stress levels as 4.9, compared with 6.2 in 2007. However, the APA say such levels remain significantly higher than the 3.7 stress rating we consider to be healthy.
"[Last] year's survey continues to reinforce the idea that we are living with a level of stress that we consider too high," says Norman B. Anderson, CEO and executive vice president of the APA, adding:
"All Americans, and particularly those groups that are most affected by stress - which include women, younger adults and those with lower incomes - need to address this issue sooner than later in order to better their health and well-being."
The surprising health implications of stress
"Stress is significantly associated with virtually all the major areas of disease," Prof. Hobfoll told MNT. "Stress is seldom the root cause of disease, but rather interacts with our genetics and our state of our bodies in ways that accelerate disease."
Some of the more well-known implications of stress that many of you may have experienced include sleep deprivation, headache, anxiety and depression. But increasingly, researchers are uncovering more and more ways in which stress can harm our health.
According to the American Heart Association (AHA), stress can influence behaviors that have negative implications for heart health.
Have you ever arrived home after a stressful day at work and reached for that bottle of wine? Many of us have.
In January 2015, MNT reported on a study that found working long hours was associated with risky alcohol use, which the study researchers say is partly down to the belief that "alcohol use alleviates stress that is caused by work pressure and working conditions."
Some of us may smoke in response to stress, while others may "comfort eat," which can lead to obesity. All of these are factors that can contribute to poor heart health by raising blood pressure and causing damage to the walls of the arteries.
According to a study reported by MNT in November 2014, stress may also reduce blood flow to the heart - particularly for women. The study researchers found that in patients with coronary heart disease, stressed women had a three times greater reduction in blood flow than stressed men.
Stress has also been associated with increased risk of heart attack. In 2012, a study published in The Lancet found that work stress may raise the risk of heart attack by 23%. And in February last year, MNT reported on a study by researchers from the University of Sydney in Australia, which found periods of intense anger or anxiety may raise heart attack risk by more than nine times.
Even after a heart attack, stress may continue to affect health. A study published in the journal Circulation in February 2015 found women were more likely to experience higher levels of mental stress following a heart attack, which results in poorer recovery.
You may be surprised to learn that stress has been associated with increased risk of diabetes. In January last year, a study published in JAMA Psychiatry found that women with symptoms of post-traumatic stress disorder (PTSD) - a condition triggered by very distressing events - were more likely to develop the condition than those without PTSD.
Periods of stress increase production of the hormone cortisol, which can increase the amount of glucose in the blood - a potential explanation for why stress has been linked to higher risk of diabetes.
For people who already have diabetes, stress can lead to poorer management of the condition. As well as interfering with stress hormones and increasing blood glucose levels, the American Diabetes Association note that stressed patients with diabetes may be less likely to take care of themselves.
"They may drink more alcohol or exercise less. They may forget, or not have time, to check their glucose levels or plan good meals," states the organization.
Alzheimer's disease affects more than 5 million people in the US and is the sixth leading cause of death in the country.
While the exact causes of the condition are unclear, past studies have suggested that stress may contribute to its development.
In March 2013, MNT reported on a study by researchers from the University of Gothenburg in Sweden, which found high levels of stress hormones in the brains of mice were associated with larger amounts of beta-amyloid plaques - proteins believed to play a role in Alzheimer's.
Another study published in 2010 by Finnish researchers found that women who had either high blood pressure or higher cortisol levels - both symptoms of stress - were more than three times as likely to develop Alzheimer's, compared with patients who did not have these symptoms.
More recently, a study published in The American Journal of Geriatric Psychiatry found that for seniors with mild cognitive impairment, anxiety could speed up progression toward Alzheimer's.
In 2012, the UK's Alzheimer's Society revealed they are embarking on a 3-year project to find out more about the association between stress and Alzheimer's disease.
"All of us go through stressful events. We are looking to understand how these may become a risk factor for the development of Alzheimer's," said lead investigator of the project Prof. Clive Holmes, of the University of Southampton in the UK.
Approximately 1 in 8 couples in the US have problems getting pregnant or sustaining a pregnancy. Increasingly, researchers are suggesting stress may be a contributing factor.
In May 2014, we reported on a study published in the journal Fertility and Sterility that found stress in men can lead to reduced sperm and semen quality, which may negatively affect fertility.
The researchers behind that study, including first author Teresa Janevic, PhD, an assistant professor at Rutgers School of Public Health in Piscataway, NJ, hypothesize that stress could trigger the release of glucocorticoids - steroid hormones that affect the metabolism of carbohydrates, fats and proteins. This could lower testosterone levels and sperm production in men.
"Stress has long been identified as having an influence on health," says Janevic. "Our research suggests that men's reproductive health may also be affected by their social environment."
And women may not be free from the effects of stress on fertility. In 2014, a study led by researchers from Ohio State University found that women with high levels of a stress-related enzyme in their saliva - alpha-amylase - were 29% less likely to become pregnant than women with low levels of this enzyme. What is more, these women were also more than twice as likely to be infertile.
How can you protect against stress-induced health problems?
Of course, the best way to reduce the risk of stress-related health implications is to tackle the stress itself.
In order to do this, you first need to recognize the symptoms of stress. Though these vary in each individual, they commonly include difficulty sleeping, fatigue, overeating or undereating and feelings of depression, anger or irritability. You may also be smoking or drinking more in an attempt to manage stress, and some people many even engage in drug abuse.
According to the NIMH, one of the best ways to tackle stress is to seek support from others, be it friends, family or religious organizations. If an individual feels they are unable to cope with stress, are having suicidal thoughts or has engaged in drug or alcohol use to try and manage stress, the organization recommends they seek help from a qualified mental health provider.
Exercise can also be an effective aid for stress. The Mayo Clinic explain that physical activity increases production of "feel-good" neurotransmitters in the brain, called endorphins. Exercise has also been associated with reduced symptoms of depression, as well as improved sleep quality.
The AHA provide some other ways to help deal with stress:
- Positive self-talk: turn negative thoughts into positive ones. Instead of saying "I can't do this," say "I'll do the best I can." Negative self-talk increases stress levels
- Emergency stress stoppers: if you start to feel stressed, count to 10 before you talk, take a few deep breaths or go for a walk
- Finding pleasure: engaging in activities you enjoy is a great way to stave off stress. Take up a hobby, watch a movie or have a meal with friends
- Daily relaxation: engage in some relaxation techniques. Meditation, yoga and tai chi have all been shown to reduce stress levels.
Written by Honor Whiteman
Most cancer cases 'caused by lifestyle, environment - not bad luck'
December 18, 2015
Most cancer cases 'caused by lifestyle, environment - not bad luck'
Lifestyle behaviors and environmental factors account for around 70-90% of cancer cases, according to new research published in the journal Nature.
The study contradicts a study published in the journal Science in January, which suggested the majority of cancer cases are down to "bad luck." In that study, Johns Hopkins researchers claimed 65% of cancer cases are a result of random DNA mutations, while the remaining 35% of cancer cases are explained by a combination of these mutations and environmental and hereditary factors. The research spurred much debate, with many scientists arguing against the "bad luck" theory. But Song Wu, PhD, lead author of this latest study and assistant professor of the Department of Applied Mathematics and Statistics at Stony Brook University in New York, notes that scientists had not conducted an alternative analysis to determine the extent to which external risk factors contribute to cancer development. "Our paper provides an alternative analysis by applying four distinct analytic approaches," he adds. Wu and colleagues applied these four approaches to the same data that were used in the earlier Science paper.
Intrinsic factors 'account for 10-30% of cancer cases'
One approach was an analysis of tissue cell turnover, which involved assessing the quantitive relationship between the lifetime risk for certain cancers - such as pancreatic, lung and colorectal cancers - and division of normal tissue stem cells. The researchers explain that if intrinsic risk factors - that is, processes that result in random DNA mutations - played a key role in cancer development, then the total number of divisions in tissue stem cells would correlate with lifetime cancer risk.
However, they found this pattern was uncommon, with intrinsic factors only accounting for around 10-30% of cancer cases. "In summary, irrespective of whether a subpopulation or all dividing cells contribute to cancer, these results indicate that intrinsic factors do not play a major causal role," say the authors.
Another approach involved mathematical analysis of recent studies on mutational cancer signatures - defined as "'fingerprints' left on cancer genomes by various mutagenic processes." The team identified 30 distinct signatures among different cancers, and they analyzed these signatures to determine the extent to which they were triggered by intrinsic or extrinsic factors - such as lifestyle and environment. From this, the researchers found that most cancers - including lung, colorectal, bladder and thyroid cancers - possessed large numbers of mutations that were likely to have been caused by extrinsic factors; only a few cancers had large proportions of intrinsic mutations, according to the team. Additionally, the researchers found strong epidemiological evidence supporting the high contribution of extrinsic factors to cancer development. For example, an analysis of immigrants who moved from countries with low cancer incidence to those with high cancer incidence revealed these individuals quickly acquired a higher cancer risk, suggesting extrinsic factors were to blame.
Fast facts about cancer
- There will be around 1,658,370 new cancer cases diagnosed in the US this year
- Around 589,430 cancer deaths will occur in the US in 2015
- Breast cancer remains the most common cancer in women, while prostate cancer is the most common cancer for men.
'People can't hide behind bad luck'
The team says their overall findings indicate that lifestyle and environmental factors account for around 70-90% of cancer cases, while intrinsic factors account for around 10-30% - findings that highly contradict those of the Science study.
Commenting on their results, the authors say:
"We have provided a new framework to quantify the lifetime cancer risks from both intrinsic and extrinsic factors on the basis of four independent approaches that are data-driven and model-driven, with and without using the stem-cell estimations
[...] Collectively, we conclude that cancer risk is heavily influenced by extrinsic factors. These results are important for strategizing cancer prevention, research and public health."
Talking to BBC News, senior author Dr. Yusuf Hannun, of the Health Sciences Center at Stony Brook, said their findings show that "people can't hide behind bad luck." "They can't smoke and say it's bad luck if they have cancer," he explained. "It is like a revolver - intrinsic risk is one bullet. And if playing Russian roulette, then maybe 1 in 6 will get cancer - that's the intrinsic bad luck." "Now, what a smoker does is add two or three more bullets to that revolver," Dr. Hannun continued. "And now, they pull the trigger. There is still an element of luck as not every smoker gets cancer, but they have stacked the odds against them. From a public health point of view, we want to remove as many bullets as possible from the chamber."
Written by Honor Whiteman
Pumpkin Seeds: Health Benefits, Nutritional Information
December 15, 2015
Pumpkin Seeds: Health Benefits, Nutritional Information
Pumpkin seeds are an edible seed typically roasted for consumption. They are a common ingredient in Greek cuisine and are also often eaten as an individual snack.
Nutritional breakdown of pumpkin seeds
According to the US Department of Agriculture (USDA) National Nutrient Database, approximately two tablespoons of unshelled pumpkin seeds (28 grams) contains 125 calories, 15 grams of carbohydrate (including 0 grams of sugar and 5 grams of fiber) and 5 grams of protein as well as 5% of your daily iron needs. Pumpkin seeds are a source of magnesium, zinc, copper and selenium.
Possible health benefits of consuming pumpkin seeds
Consuming fruits and vegetables of all kinds has long been associated with a reduced risk of many lifestyle-related health conditions. Many studies have suggested that increasing consumption of plant foods like pumpkin seeds decreases the risk of obesity, diabetes, heart disease and overall mortality while promoting healthy complexion and hair, increased energy and overall lower weight.
The benefits of magnesium
Pumpkin seeds are exceptionally high in magnesium, one of the seven essential macrominerals. Two tablespoons of pumpkin seeds contain 74 mg of magnesium, about 1/4th of the daily recommended dietary allowance. Magnesium plays an important role in over 300 enzymatic reactions within the body, including the metabolism of food and synthesis of fatty acids and proteins. Magnesium is involved in neuromuscular transmission and activity and muscle relaxation. Magnesium deficiency, especially prevalent in older populations, is linked to insulin resistance, metabolic syndrome, coronary heart disease and osteoporosis.
Magnesium is important for bone formation. High magnesium intakes are associated with a greater bone density and have shown to be effective for decreasing the risk of osteoporosis in postmenopausal women.
For every 100 mg/day increase in magnesium intake, the risk of developing type 2 diabetes decreases by approximately 15%. Low magnesium levels can impair insulin secretion and lower insulin sensitivity.
Improvement in lipid profiles has been seen with an intake of 365 mg of magnesium per day.
Heart and liver health
Pumpkin seeds are rich in omega-3 and omega-6 fatty acids, antioxidants and fiber. This combination has benefits for both your heart and liver. The fiber in pumpkin seeds helps lower the total amount of cholesterol in the blood and decrease the risk of heart disease, while research to date suggests that omega-3s can decrease the risk for thrombosis and arrhythmias, which lead to heart attack, stroke and sudden cardiac death. Omega-3s may also decrease LDL, total cholesterol and triglyceride levels, reduce atherosclerotic plaque, improve endothelial function and slightly lower blood pressure.
Pumpkin seeds are a rich source of tryptophan, an amino acid. Tryptophan has been used to treat chronic insomnia because the body coverts it into melatonin, the "sleep hormone." A study published in Nutritional Neuroscience suggested that consuming tryptophan from a gourd seed alongside a carbohydrate source was comparable to pharmaceutical grade tryptophan for the treatment of insomnia. Having a few pumpkin seeds before bed, with a small amount of carbohydrates such as a piece of fruit, may be beneficial in providing your body with the tryptophan needed for melatonin production.
It is estimated that over 80% of women worldwide have inadequate zinc intake. Low levels of zinc alter circulating levels of multiple hormones associated with the onset of labor. In addition to this, zinc is essential for normal immune function and prevention of uterine infections. All of these could potentially contribute to preterm birth.
How to incorporate more pumpkin seeds into your diet
- Top salads with pumpkin seeds
- Make homemade granola with a mixture of nuts, pumpkin seeds and dried fruit
- Brush pumpkin seeds with olive oil, season with cumin and garlic powder and bake until brown and toasted
- Make your own pumpkin seed butter (like peanut butter) by blending whole, raw pumpkin seeds in a food processor until smooth.
Risks and precautions
Seeds have a high fat content so they are prone to rancidity. Keep pumpkin seeds in a cool, dark and dry place to improve shelf life. If stored properly, pumpkin seeds will keep for 3-4 months. It is the total diet or overall eating pattern that is most important in disease prevention and achieving good health. It is better to eat a diet with variety than to concentrate on individual foods as the key to good health.
Written by Megan Ware RDN LD
How the herpes virus reactivates under stress
December 12, 2015
How the herpes virus reactivates under stress
Cold sores caused by the herpes virus resurface under stress; now, scientists have discovered the cellular mechanism that allows this to happen, according to research published in Cell Host and Microbe
About 90% of the US population have the herpes simplex virus (HSV), which leads to cold sores, recurrent eye infections, genital lesions, and in rare cases encephalitis, an inflammation of the brain with a 30% mortality rate - or 70-80% if left untreated.
The closely related varicella zoster virus also causes chicken pox and shingles.
Previous studies have connected a protein called JNK to stress. The team already knew that HSV lays dormant in neurons and that stress triggers viral reactivation. Corticosteroid, a natural stress hormone, has been shown to activate the JNK pathway and trigger neuron death.
New research was carried out by a team at the University of North Carolina (UNC) School of Medicine, where senior author Mohanish Deshmukh specializes in neuron survival and death.
The team started by forcing the virus to become latent in mouse primary neurons and then to become reactivated. This enabled them to study specific cellular protein pathways potentially involved in viral reactivation.
Fast facts about HSV
- There are two types of HSV, and both are highly infectious
- HSV-1 is mainly transmitted by oral-to-oral contact, causing "cold sores" and sometimes genital herpes
- HSV-2 is a sexually transmitted disease that can cause genital herpes.
Blocking the JNK pathway prevents reactivation
To find out if the virus could sense when the neurons are under stress and activate an escape pathway, they focused on the protein JNK. To a dish of mouse neurons, first author and virologist Anna Cliffe added chemicals that mimic the loss of nerve growth factor; neurons need this factor to remain healthy. She also used a corticosteroid to mimic what happens in the body, as stress causes high levels of corticosteroids to be released.
Results showed that the JNK protein pathway was activated just before the virus began to leave neurons. When the JNK pathway was blocked, the virus could no longer reactivate.
The team also found that the virus can be reactivated even when the viral DNA in neurons is repressed.
Researchers found that the histones associated with viral DNA did not undergo the process of demethylation that allows tightly packaged DNA, known as chromatin, to become more open so that gene expression - including HSV gene expression - can occur; this is how the virus becomes reactivated.
This is surprising, because normally, the methyl marks - or epigenetic modifications - need to be removed before DNA can be opened; in this case, gene expression occurred even when the methyl marks were still there.
The experiments show that the virus is able to modify its chromatin through phosphorylation of the histone next to the methyl mark; the methyl marks act as a methyl/phospho switch or, as Deshmukh says, "brakes to refuse gene expression."
He explains that "phosphorylation releases the brakes just enough so that a little bit of viral gene expression can occur," and phosphorylation also depends on the activation of the JNK pathway.
The experiments link the stress-activated pathway to the very earliest changes in the viral DNA.
Once the initial brakes are eased, full viral gene expression requires removal of the repressive histone methylation in order for the virus to complete the reactivation process. This, in turn, leads to full virus formation outside the neuron.
From there, disease states such as cold sores and encephalitis are born.
"We're excited about the possibility that this stress-activation pathway exists in humans. All of the elements of these pathways are found in human neurons. And we know that stress reactivates herpes simplex virus in humans."
The researchers hope to replicate the results in human neurons. If they can confirm that the JNK pathway is crucial for viral reactivation in humans, this could lead to treatments for diseases linked to both HSV and other related viruses. In Cliffe's view, the neurons identified represent "a good therapeutic target."
Written by Yvette Brazier
Honey: Health Benefits, Uses and Risks
November 16, 2015
Honey: Health Benefits, Uses and Risks
Honey is a sweet food made by bees using nectar from flowers. Bees first convert the nectar into honey by a process of regurgitation and evaporation, then store it as a primary food source in wax honeycombs inside the beehive. Honey can then be harvested from the hives for human consumption.
Honey is graded by color, with the clear, golden amber honey often at a higher retail price than darker varieties. Honey flavor will vary based on the types of flower from which the nectar was harvested. Both raw and pasteurized forms of honey are available. Raw honey is removed from the hive and bottled directly, and as such will contain trace amounts of yeast, wax and pollen. Consuming local raw honey is believed to help with seasonal allergies due to repeated exposure to the pollen in the area. Pasteurized honey has been heated and processed to remove impurities. This MNT Knowledge Center feature is part of a collection of articles on the health benefits of popular foods. It provides a nutritional breakdown of honey and an in-depth look at its possible health benefits, how to incorporate more honey into your diet and any potential health risks of consuming honey.
Nutritional breakdown of honey
According to the US Department of Agriculture (USDA) National Nutrient Database, one tablespoon of honey (approximately 21 grams) contains 64 calories, 17.3 grams of carbohydrate (17.3 grams of sugar no fiber), 0 grams of fat and 0 grams of protein. Honey contains negligible amounts of vitamins and minerals. Choosing honey over sugar results in a more gradual rise in blood sugar levels that is believed to help with hunger levels. Honey is also known to have antioxidant, antimicrobial and soothing effects.
Possible benefits of consuming honey
The World Health Organization (WHO) and American Academy of Pediatrics recommend honey as a natural cough remedy. A 2007 study by Penn State College of Medicine suggested that honey reduced nighttime coughing and improved sleep quality in children with upper respiratory infection better than the cough medicine dextromethorphan or no treatment.
Honey may be effective at treating heartburn, according to research reported in the BMJ. Researchers have suggested that this may be due to the viscosity of honey coating the upper gastroesophageal tract and preventing stomach acid from rising.
Honey contains the protein defensin-1, which has the ability to kill bacteria. Raw, unpasteurized honey can be used as a topical agent for wounds but should not be used in place of a prescribed topical agent.
How to incorporate more honey into your diet
Experimentation is key when substituting honey for sugar. Baking with honey can cause excess browning and moisture. As a general rule, use ¾ cup of honey for every one cup of sugar, reduce the liquid in the recipe by 2 tablespoons and lower the oven temperature by 25 degrees Fahrenheit.
- Use honey to sweeten your dressings or marinades
- Stir honey into coffee or tea
- Drizzle honey on top of toast or pancakes
- Mix honey into yogurt, cereal, or oatmeal for a more natural sweetener
- Spread raw honey over whole grain toast and top with peanut butter.
Or, try these healthy and delicious recipes developed by registered dietitians:
Honey-glazed roasted sweet potatoes
Basil honey mango sorbet
Honey Dijon vinaigrette with arugula, pear and walnut salad
Grilled fruit kebabs
If stored in an airtight container, honey can be kept indefinitely.
Potential health risks of consuming honey
It is the total diet or overall eating pattern that is most important in disease prevention and achieving good health. It is better to eat a diet with variety than to concentrate on individual foods as the key to good health. Honey is still a form of sugar and intake should be moderate. The American Heart Association recommends that women get no more than 100 calories a day from added sugars; men no more than 150 calories a day. This is a little over two tablespoons for women and three tablespoons for men. Honey may contain botulinum endospores that cause infant botulism, a rare but serious type of food poisoning that can result in paralysis. Even pasteurized honey has a chance of containing these spores. For this reason, it is recommended that infants under 1 year do not consume honey.
Written by Megan Ware RDN LD and Mary Curnutte, Nutrition Intern
Processed Meat Increases Risk for Colon Cancer, Says IARC
October 28, 2015
Processed Meat Increases Risk for Colon Cancer, Says IARC
Eating processed meat, including bacon, cold cuts, sausages, and hot dogs, can increase the risk of developing colorectal cancer, according to a new report from the World Health Organization (WHO). The International Agency for Research on Cancer (IARC), the cancer agency of the WHO, has classified consumption of processed meat as "carcinogenic to humans" (Group 1) on the basis of sufficient evidence for colorectal cancer. In addition, says the group, there was a positive association with stomach cancer.
The IARC has also classified the consumption of red meat as being "probably carcinogenic to humans" (Group 2A). The decision was based on all of the relevant data that show strong mechanistic evidence supporting a carcinogenic effect. This association was observed mainly for colorectal cancer but also for pancreatic cancer and prostate cancer. An analysis of data from 10 studies estimated that every 50-g portion of processed meat eaten daily increases the risk for colorectal cancer by about 18%. The IARC acknowledges that it is more difficult to estimate the cancer risk related to consuming red meat (that is not processed) because the evidence linking it to cancer is not as strong as it is for processed meats. However, if the association of red meat and colorectal cancer were proven to be causal, data from the same studies suggest that the risk for colorectal cancer could increase by 17% for every 100-g portion of red meat eaten daily.
"For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed," says Kurt Straif, MD, PhD, head of the IARC Monographs Programme. "In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance."
A summary of the evaluations was published online October 26 in the Lancet Oncology. The consumption of meat varies greatly between countries, from less than 5% to up to 100%. For processed meat, it varies from less than 2% to 65%. The mean intake of red meat by those who consume it is about 50 to 100 g per person per day, with high consumption equalling more than 200 g per person per day, according to the report. Less information is available on the consumption of processed meat.
Previous Data Point to Risk
As previously reported by Medscape Medical News, the long-term consumption of red meat and processed meat has repeatedly been associated with a higher risk for certain cancers, especially colorectal cancer. Research has also suggested a link between the heavy consumption of red meat during premenopausal years and an increased risk for breast cancer. Other data show that smoking and consuming diets rich in animal products have the strongest correlations with cancer incidence rates. The strongest correlation with animal products was seen in cancers of the female breast, corpus uteri, kidney, ovaries, pancreas, prostate, testicles, and thyroid, and in multiple myeloma. In recent years, several organizations, including the American Institute for Cancer Research (AICR), the American Cancer Society, and the US Department of Agriculture, have issued dietary guidelines aimed at encouraging healthier eating habits, increasing physical activity, and curbing rising obesity rates.
Some of the most extensive data on diet/lifestyle and cancer risk have been released by the AICR, which confirmed that consumption of red meat and processed meat increases the risk for colorectal cancer. The AICR recommended limiting the intake of red meat and processed meat, eating mostly foods of plant origin, and limiting the consumption of energy-dense foods, which include sugary drinks. In their 2011 report, they estimated that about 45% of colorectal cancer cases could be prevented if people consumed more fiber-rich plant foods, consumed less meat and alcohol, became more physically active, and maintained a healthy weight.
The IARC convened a working group of 22 experts from 10 countries who reviewed the accumulated scientific literature. They experts considered more than 800 studies that investigated associations of more than a dozen types of cancer with the consumption of red meat or processed meat in many countries and populations with diverse diets. The most influential evidence came from large, prospective, cohort studies conducted over the past 20 years. The largest body of epidemiologic data concerned colorectal cancer. For example, one meta-analysis of 10 cohort studies reported a statistically significant dose-response relationship, with a 17% increased risk (95% confidence interval [CI], 1.05 - 1.31) per 100 g per day of red meat and an 18% increase (95% CI, 1.10 - 1.28) per 50 g per day of processed meat (PLoS One. 2011;6:e20456). Data were also available for more than 15 other types of cancer. The most positive associations were observed in cohort studies and population-based case-control studies between consumption of red meat and cancers of the pancreas and the prostate (primarily advanced prostate cancer) and between consumption of processed meat and cancer of the stomach.
Accolades and Thumbs Down
Susan Gapstur, MPH, PhD, vice president of epidemiology, American Cancer Society, commented that "this is an important step in helping individuals make healthier dietary choices to reduce their risk of colorectal cancer in particular." "In general, the IARC conclusion is consistent with the World Cancer Research Fund/AICR Continuous Update Project, which found the evidence convincing that diets high in red meat and processed meat are associated with increased risk of colorectal cancer," she said in a statement. Classifying processed meat as carcinogenic and red meat as probably carcinogenic to humans is not unexpected, she pointed out. "Indeed, based on earlier scientific studies, including findings from the American Cancer Society's Cancer Prevention Study II, the American Cancer Society has recommended limiting consumption of red and processed meat specifically since 2002." Dr Gapstur added that the IARC report is also in line with the US 2015 Dietary Guidelines for Americans Advisory Committee, which recommends a healthful dietary pattern that is lower in red meat and processed meat.
Not surprisingly, the release of the IARC report was not well received among the meat industry, which immediately pushed back against the findings. In a release, the North American Meat Institute (NAMI) said that classifying red meat and processed meat as cancer "hazards" defies "both common sense and numerous studies showing no correlation between meat and cancer and many more studies showing the many health benefits of balanced diets that include meat." "It was clear sitting in the IARC meeting that many of the panelists were aiming for a specific result despite old, weak, inconsistent, self-reported intake data," said Betsy Booren, PhD, NAMI vice president of scientific affairs. "They tortured the data to ensure a specific outcome. "Red and processed meat are among 940 agents reviewed by IARC and found to pose some level of theoretical 'hazard.' Only one substance, a chemical in yoga pants, has been declared by IARC not to cause cancer," said Dr Booren.
The National Cattlemen's Beef Association (NCBA) noted that "after 7 days of deliberation in Lyon, France, IARC was unable to reach a consensus agreement from a group of 22 experts in the field of cancer research, something that IARC has proudly highlighted they strive for and typically achieve. In this case, they had to settle for 'majority' agreement." "Cancer is a complex disease that even the best and brightest minds don't fully understand," said Shalene McNeill, PhD, RD, executive director of human nutrition research at the NCBA, in their press release. "Billions of dollars have been spent on studies all over the world, and no single food has ever been proven to cause or cure cancer. "The opinion by the IARC committee to list red meat as a probable carcinogen does not change that fact," said Dr McNeill. "The available scientific evidence simply does not support a causal relationship between red or processed meat and any type of cancer."
Source: The lancet
Keep moving to prevent osteoarthritis, say physicists
October 22, 2015
Keep moving to prevent osteoarthritis, say physicists
Osteoarthritis in the knee is a painful condition affecting nearly half of all Americans at some time - and two thirds of obese adults. Research suggesting that physical activity could help prevent it has been presented this week at the AVS 62nd International Symposium and Exhibition, in San Jose, CA.
Osteoarthritis is a degenerative bone disease resulting from a reduction in the cartilage, leading to an increase in friction. Cartilage is a firm, rubbery material covering the ends of the bones in the knee joint. It reduces friction in the joint and acts as a "shock absorber." When cartilage becomes damaged or deteriorates, it limits the knee's normal movement and can cause significant pain, and eventually the need for knee replacement surgery. About 80% of the volume of cartilage tissue is made up of synovial fluid. This fluid is needed to support weight and lubricate joint surfaces. The loss of synovial fluid that causes the decrease in cartilage thickness, increase in friction, bone degradation and joint pain of osteoarthritis. Since cartilage is porous, the synovial fluid is squeezed out of the holes over time. In fact, it is constantly leaking out into the membrane-walled cavity between the upper and lower leg bones.
What stops cartilage from deflating?
Yet the symptoms associated with osteoarthritis usually take decades to develop; so, what prevents the cartilage from deflating over the course of days, months or years, in the joints? David Burris, an assistant professor in the Mechanical Engineering Department at the University of Delaware, and colleagues believe they know how motion can cause cartilage to reabsorb liquid that leaks out. Scientists have previously hypothesized that if movement occurs faster than the fluid can diffuse, then continuous knee movement could prevent deflation. Using a small sphere articulated against a cartilage plug, they showed that interstitial pressure was maintained indefinitely, if the contact area moved faster than the diffusive speed of the synovial fluid. However, it remained unclear how a knee joint does not become deflated, given the long periods of time spent sitting and standing each day, without active input. In other words, how does cartilage reabsorb the fluid that leaks out when people are not moving?
Fast facts about arthritis
- In 2013, 1 in 5 Americans had doctor-diagnosed arthritis
- 49.7% of over-65s had been diagnosed with arthritis
- By 2030, it is projected that 67 million Americans over 18 will have an arthritis diagnosis.
Pressure forces fluid back into the cartilage
Burris suggested that the reabsorption process might be driven by hydrodynamic pressurization. The term hydrodynamic refers to the lubricating principle involved in the working of bearings; in this case, the knee joint. Hydrodynamic pressurization occurs when the relative motion of two surfaces causes fluid between them to accelerate in the shape of a triangular wedge. For example, when a normal tire travels quickly over water, pressure builds until a film forms to lubricate the interface; this is called hydroplaning. Hydroplaning leads to a complete loss of frictional control. If the tire were porous, however, the exterior fluid pressure could force fluid back into the tire. To investigate whether hydrodynamic pressurization could refill deflated cartilage, the researchers placed larger-than-average cartilage samples against a glass flat to ensure that there would be a wedge.
They found that at slow sliding speeds (less than would occur in a joint at typical walking speeds) cartilage thinning and an increase in friction occurred over time; but as the sliding speed increased toward typical walking speeds, the effect was reversed.
They concluded that hydrodynamic pressures, which force fluid flow into the cartilage, must have counteracted the fluid that had been exuded.
"We observed a dynamic competition between input and output [of synovial fluid]. We know that cartilage thickness is maintained over decades in the joint, and this is the first direct insight into why. It is activity itself that combats the natural deflation process associated with interstitial lubrication."
Written by Yvette Brazier
Novel theoretical approach to reduce antibiotic resistance
October 13, 2015
Novel theoretical approach to reduce antibiotic resistance
The combination and sequence of antibiotics can promote or hinder the development of antibiotic-resistant bacteria
It is estimated that each year in the United States 2 million people become infected with bacteria that are resistant to one or more types of antibiotics, and at least 23,000 people will die because of these infections. This problem is being exacerbated by overuse of antibiotics for livestock and also in community clinical practice. This overuse, combined with the slow pace of novel drug discovery is a growing threat to public health. In response to this, Moffitt Cancer Center researchers have developed a novel mathematical method inspired by Darwinian evolution to use current antibiotics to eliminate or reduce the development of antibiotic-resistant bacteria.
According to the Centers for Disease Control, one of the core actions that can be taken to fight antibiotic-resistant infections is to improve the use of antibiotics that currently exist. One approach to achieve this is by using different combinations or sequences of antibiotics; however, given the high number of antibiotics in existence, it would be extremely difficult to experimentally identify the best combination or sequence of drugs. Moffitt researchers overcame this problem by developing a novel mathematical approach to analyze antibiotic resistance. They showed that the ability of the bacterium E. coli to survive in antibiotics could be either promoted or hindered depending on the sequence of antibiotics given. They discovered that approximately 70 percent of different sequences of 2 to 4 antibiotics lead to resistance to the final drug.
"Our results suggest that, through careful ordering of antibiotics, we may be able to steer evolution to a dead end from which resistance cannot emerge," said Daniel Nichol, lead author and graduate student jointly in the Oxford University Department of Computer Science and Moffitt's Department of Integrated Mathematical Oncology. "Our results can be easily tested in the laboratory, and if validated could be used in clinical trials immediately, as all of the compounds we studied are FDA approved and commonly prescribed," said Jacob G. Scott, M.D., senior author and member of Moffitt's Radiation Oncology and Integrated Mathematical Oncology Departments.The researchers explained that their results also serve as a caution to healthcare workers, as the careless or random prescription of drugs that occurs could inadvertently lead to antibiotic resistance.
"While I'm an oncologist, the problem of the evolution of resistance to antibiotics is completely analogous to that of cancer's evolution of resistance to targeted therapy, and the mathematical model we've used can be applied to both situations. Our next efforts are jointly focused on targeted therapy in lung cancer as well as on validating our existing results in bacteria," said Scott.
The study was published online in the journal PLoS Computational Biology. Funding support was received through the Engineering and Physical Sciences Research Council (OUCL/DN/2013 and EP/I017909/1), the National Institutes of Health Loan Repayment Program, the National Cancer Institute Integrative Cancer Biology Program (U54 CA113007), the National Cancer Institute Physical Sciences in Oncology Centers (U54 CA143970), the Veterans Affairs Merit Review Program, the National Institutes of Health (AI072219-05, AI063517-07) and the Geriatric Research Education and Clinical Center VISN 10.
Materials provided by H. Lee Moffitt Cancer Center & Research Institute
To live longer, replace 1 hour of sitting with walking daily
October 05, 2015
To live longer, replace 1 hour of sitting with walking daily
When it comes to staying healthy, the advice is endless - drink more water, exercise more, take your vitamins, eat oily fish, drink more coffee, drink less coffee. But a new study appears to simplify the key to long-term health; it suggests that by replacing 1 hour of sitting each day with walking, we can decrease our chance of early death by 12-14%
The study, published in the International Journal of Behavioral Nutrition and Physical Activity, was conducted by researchers at the University of Sydney in Australia and included over 200,000 adults who were middle-aged or older.
According to the Centers for Disease Control and Prevention (CDC), adults need at least 150 minutes of moderate-intensity aerobic activity - such as brisk walking - every week, as well as muscle-strengthening activities on 2 or more days each week.
Although 150 minutes may seem like a lot of time, doing it in 10-minute increments over the course of the week counts, too.
Prof. Emmanuel Stamatakis, lead study author, notes that previous studies "established the benefits of adequate physical activity or sleep and the risks of too much sitting, but this is the first to look at what happens when we replace one activity with an equal amount of another."
He and his team point to work hours, which account for over 50% of total waking time, adding that "workers in many professions spend on average more than 70% of their work time sitting."
Sedentary activity, physical activity and sleep are all part of a 24-hour day, but the researchers say previous investigations have largely examined each behavior "without considering what time-dependent behaviors are being displaced." Their latest study focuses on the effects of replacing the behaviors and compares this with health outcomes in general, including mortality.
To conduct their research, the team used statistical modeling of health data from study subjects who took part in the 45 and Up Study, which spanned a 4-year period.
'Inactivity is a bigger health problem than previously thought'
The team found that swapping just 1 hour of sitting each day with standing results in a 5% decrease in risk of early death. Additionally, for those who were not getting enough sleep, swapping just 1 hour of sitting with sleeping each day resulted in a 6% decrease in risk of early death.
Interestingly, when 1 hour of walking or exercising each day was replaced with sitting or some other sedentary behavior, the team found a 13-17% increase in early death risk.
"The results show that inactivity is an even bigger health challenge than we initially thought," notes Prof. Stamatakis, adding:
"With the average person sitting watching 2-3 hours of TV a day, there is definitely scope for people to get off the couch and be more active.
But it's also time for governments to realize that physical activity cannot be treated as the sole responsibility of individuals because we live in a physical activity-hostile world. Finger-pointing at people because they do not do the right thing has not solved any health problem to date, and it is not going to solve the problem of inactivity either."
Given that there are only 24 hours in a day, he and his team say their research shows we must be scrupulous in how we choose to spend our time.
Standing is a 'straightforward intervention'
Although the study's strength lies in its large, population-based sample size, it does have some limitations. For example, the study variables were analyzed through a self-administered questionnaire, which does leave room for some bias and error, including over-reporting of physical activity or under-reporting of sitting time, "due to social desirability bias."
Still, the team says their results could help with implementing a "long-term vision that makes physical activity the easy and convenient option."
They note that data from both the US and UK reveal that, on average, people over the age of 70 spend around 65-80% of their waking time being sedentary, so substituting some of this time with standing or light activity could have a positive health impact.
"Unlike promoting physical activity, substitution of desk-based sitting for standing is a relatively straightforward intervention that has no additional time and location requirements," they say.
The researchers add that implementing better infrastructure in our environments, including more cycleways, better-connected parks and improved public transport could seamlessly integrate physical activity into our everyday lives.
Written by Marie Ellis
How a Big Mac affects your body in 1 hour
September 29, 2015
How a Big Mac affects your body in 1 hour
With more than 36,000 restaurants around the globe, chances are you have eaten at a McDonald's at one point or another, and many of you are likely to have indulged in one of the chain's most popular offerings: the Big Mac. It goes without saying that, although tasty, the Big Mac is not the healthiest food option. And now, a new infographic claims to show exactly what this world-famous sandwich does to our body within an hour of eating it.
A Big Mac contains 540 calories and 25 grams of fat. Consuming this sandwich alone - without the fries and soda that often accompany it - makes up more than 25% of an adult's daily recommended calorie intake and over 40% of the recommended daily fat intake. The sandwich also contains 940 milligrams of salt - the majority of the 1,500 mg daily salt intake recommended by the American Heart Association. While most of us are aware that eating this sandwich is unlikely to be good for us, the nutritional values of food are often put to one side in favor of taste and convenience; around 50 million Americans each day visit fast food restaurants, with more than a fifth indulging in fast food twice weekly. But would you be deterred from opting for such foods if you knew what they did to your body after consumption? The website Fast Food Menu Price has created an infographic claiming to show how a Big Mac affects the body 10, 20, 30, 40 and 60 minutes after eating it.
A Big Mac 'takes 3 days to digest'
Within 10 minutes of eating a Big Mac, the high calorie content begins to increase blood sugar levels to abnormal levels, according to the infographic. Talking to The Independent, however, dietitian and spokeswoman for the British Dietetic Association Priya Tew says that while blood sugar levels will increase, they are unlikely to reach abnormal levels. The sandwich - like other "junk food" - will also trigger the release of brain chemicals such as dopamine, which activate the brain's reward system and provide a feeling of pleasure. The infographic says this is comparable to the effects of cocaine. After 20 minutes, addictive ingredients such as high-fructose corn syrup - present in high levels in the Big Mac bun - and sodium will set in, making us crave more, according to the infographic. After another 10 minutes, the high salt content of the Big Mac begins to take its toll on the body, leading to dehydration. Because symptoms of dehydration are similar to those of hunger, the infographic warns that you may want more food at this point.
However, Tew disagrees with this fact. "I just converted 970 mg in sodium and it works out as 2.4 g of salt," she told The Independent. "It's not enough to cause dehydration in my opinion. But it is a salty food so it's good to be aware."
If you often feel hungry just after eating a Big Mac, this may be due to body's inability to control blood sugar.
"The first time you consume a high-calorie meal, your insulin response can reduce your glucose levels making you want to eat more," the infographic explains. "The high-fructose corn syrup in the Big Mac bun is quickly absorbed by the GI [gastrointestinal] tract, causing insulin spikes and even greater hunger pangs."
Possibly the most shocking claim the infographic makes about a Big Mac's effect on the body is that it can take more than 3 days to fully digest because of its fat content; the body normally takes around 24-72 hours to digest food.
However, Tew believes that while fatty foods do take longer to digest, the 3-day time frame for a Big Mac is likely to be an exaggeration.
While nutritionists and health experts have questioned the accuracy of this infographic, there is one thing they all agree on: a Big Mac should be consumed in moderation.
"If you want to enjoy a Big Mac, try to keep it an occasional indulgence," the infographic concludes. "The burger's ingredients can cause serious harm to your body, especially when you consume them on a regular basis."
Written by Honor Whiteman
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