Hamilton, ON (March 31, 2021) - A global study led by Hamilton scientists has found a link between eating processed meat and a higher risk of cardiovascular disease. The same study did not find the same link with unprocessed red meat or poultry.
The information comes from the diets and health outcomes of 134,297 people from 21 countries spanning five continents, who were tracked by researchers for data on meat consumption and cardiovascular illnesses.
After following the participants for almost a decade, the researchers found consumption of 150 grams or more of processed meat a week was associated with a 46 per cent higher risk of cardiovascular disease and a 51 per cent higher risk of death than those who ate no processed meat.
However, the researchers also found moderate levels of consumption of non-processed meats had a neutral effect on health.
"Evidence of an association between meat intake and cardiovascular disease is inconsistent. We therefore wanted to better understand the associations between intakes of unprocessed red meat, poultry, and processed meat with major cardiovascular disease events and mortality," said Romaina Iqbal, first author of the study and an associate professor at the Aga Khan University in Karachi, Pakistan.
"The totality of the available data indicates that consuming a modest amount of unprocessed meat as part of a healthy dietary pattern is unlikely to be harmful," said Mahshid Dehghan, investigator for the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences.
The Prospective Urban Rural Epidemiology (PURE) study was launched in 2003 and is the first multinational study that provides information on the association between unprocessed and processed meat intakes with health outcomes from low, middle and high-income countries.
"The PURE study examines substantially more diverse populations and broad patterns of diet, enabling us to provide new evidence that distinguishes between the effects of processed and unprocessed meats," said senior author Salim Yusuf, executive director of the PHRI.
Participants' dietary habits were recorded using food frequency questionnaires, while data was also collected on their mortality and major cardiovascular disease events. This allowed researchers to determine the associations between meat consumption patterns and cardiovascular disease events and mortality.
The authors believe that additional research may improve current understanding of the relationship between meat consumption and health outcomes. For example, it is unclear what study participants with lower meat intakes were eating instead of meat, and if the quality of those foods differed between countries.
Non-meat food substitutes may have implications in further interpreting the associations between meat consumption and health outcomes. Nonetheless, the study's authors believe their findings "indicate that limiting the intake of processed meat should be encouraged."
DALLAS, March 31, 2021 -- Following a routine of regular physical activity combined with a diet including fruits, vegetables and other healthy foods may be key to middle-aged adults achieving optimal cardiometabolic health later in life, according to new research using data from the Framingham Heart Study published today in the Journal of the American Heart Association, an open access journal of the American Heart Association.
Cardiometabolic health risk factors include the metabolic syndrome, a cluster of disorders such as excess fat around the waist, insulin resistance and high blood pressure. Presence of the metabolic syndrome may increase the risk of developing heart disease, stroke and Type 2 diabetes.
Researchers noted it has been unclear whether adherence to both the U.S. Department of Health and Human Services' 2018 Physical Activity Guidelines for Americans and their 2015-2020 Dietary Guidelines for Americans - as opposed to only one of the two - in midlife confers the most favorable cardiometabolic health outcomes later in life. The physical activity guidelines recommend that adults achieve at least 150 minutes of moderate or 75 minutes of vigorous physical activity per week, such as walking or swimming. The dietary guidelines, which were updated in January 2021, offer suggestions for healthy eating patterns, nutritional targets and dietary limits.
In an analysis of data from participants of the Framingham Heart Study, which began more than 70 years ago in Framingham, Massachusetts, investigators examined data from 2,379 adults ages 18 and older and their adherence to the two guidelines. They observed that meeting a combination of the two recommendations during midlife was associated with lower odds of metabolic syndrome and developing serious health conditions as participants aged in their senior years in 2016-2019 examinations.
"Health care professionals could use these findings to further promote and emphasize to their patients the benefits of a healthy diet and a regular exercise schedule to avoid the development of numerous chronic health conditions in the present and in later life," said corresponding author Vanessa Xanthakis, Ph.D., FAHA, assistant professor of medicine and biostatistics in the Section of Preventive Medicine and Epidemiology at Boston University School of Medicine in Boston. "The earlier people make these lifestyle changes, the more likely they will be to lower their risk of cardiovascular-associated diseases later in life."
Study participants were selected from the third generation of the Framingham Heart Study. Participants (average age 47, 54% women) were examined between 2008 and 2011. Researchers evaluated physical activity using a specialized device known as an omnidirectional accelerometer. The device, which tracks sedentary and physical activity, was worn on the participant's hip for eight days. Researchers also collected dietary information from food frequency questionnaires to measure the kinds and levels of food and nutrients consumed.
In this investigation, researchers observed that among all participants, 28% met recommendations of both the physical activity and dietary guidelines, while 47% achieved the recommendations in only one of the guidelines. Researchers also observed that:
participants who followed the physical activity recommendations alone had 51% lower odds of metabolic syndrome;
participants who adhered to the dietary guidelines alone had 33% lower odds; and
participants who followed both guidelines had 65% lower odds of developing metabolic syndrome.
"It is noteworthy that we observed a dose-response association of adherence to diet and physical activity guidelines with risk of cardiometabolic disease later in life," Xanthakis said. "Participants who met the physical activity guidelines had progressively lower risk of cardiometabolic disease as they increased adherence to the dietary guidelines."
All study participants were white adults, therefore, the findings cannot be generalized to people in other racial or ethnic groups. Additional studies with a multiethnic participant sample are needed, researchers said.
The study by a team of researchers at USC, UCLA and the University of Georgia, Athens, finds a direct connection between particular bacteria in the gut and impaired brain function.
New research shows how drinking sugary beverages early in life may lead to impaired memory in adulthood.
The study, published today in Translational Psychiatry, also is the first to show how a specific change to the gut microbiome -- the bacteria and other microorganisms growing in the stomach and intestines -- can alter the function of a particular region of the brain.
According to the Centers for Disease Control and Prevention, sugar-sweetened beverages are a leading source of added sugars in Americans' diets. Nearly two-thirds of young people in the United States consume at least one sugary drink each day.
Neuroscientist Scott Kanoski, associate professor of biological sciences at the USC Dornsife College of Letters, Arts and Sciences, has studied the link between diet and brain function for years. His research has shown that consumption of sugary beverages impairs memory function in rats and that those same drinks change the gut microbiome.
In the current study, Kanoski and researchers at UCLA and the University of Georgia, Athens, sought to find out if a direct link exists between changes to the microbiome and memory function.
The scientists gave adolescent rats free access to a sugar-sweetened beverage similar to those that humans drink.
When the rats grew to be adults after about a month, the researchers tested their memories using two different methods. One method tested memory associated with a region of the brain called the hippocampus. The other method tested memory function controlled by a region called the perirhinal cortex.
The researchers found that, compared to rats that drank just water, the rats that consumed high levels of sugary drink had more difficulty with memory that uses the hippocampus. Sugar consumption did not affect memories made by the perirhinal cortex.
"Early life sugar consumption seems to selectively impair their hippocampal learning and memory," said study lead author Emily Noble, assistant professor in the UGA College of Family and Consumer Sciences and a former postdoctoral fellow at USC Dornsife.
The scientists then checked the rats' gut microbiomes and found differences between those that drank the sweet beverage and those that drank water. The sugar drinkers had larger populations of two particular species of gut bacteria: Parabacteroides distasonis and Parabacteroides johnsonii.
The researchers then asked if the Parabacteroides bacteria could, without the help of sugar, affect the rats' memory function. They transplanted Parabacteroides bacteria that were grown in the lab into the guts of adolescent rats that drank just water. The rats receiving the bacteria showed memory impairment in the hippocampus when they grew to adulthood much the same as the sugar-drinking rats.
The scientists also found that, unlike the sugar-drinking rats, the transplanted rats also showed memory impairment in the perirhinal cortex. This difference provides further evidence that altered brain function associated with diet may actually be rooted in changes to the gut microbiome.
Previous studies have transplanted the entire gut microbiome from one group of animals to another, producing similar changes to brain function. However, this study is among the first to do so with just two specific species.
"It was surprising to us that we were able to essentially replicate the memory impairments associated with sugar consumption not by transferring the whole microbiome, but simply by enriching a single bacterial population in the gut," said Kanoski, who is a corresponding author on the study.
Finally, the scientists examined the activity of genes in the hippocampus, comparing rats that drank the sugary beverage to those that drank just water and comparing water drinkers to those transplanted with Parabacteroides.
Gene activity did, in fact, change in both the rats that consumed the sugar-sweetened beverages and the rats transplanted with Parabacteroides. The genes that were affected control how nerve cells transmit electrical signals to other nerve cells and how they send molecular signals internally.
The results of this study confirm a direct link, on a molecular level, between the gut microbiome and brain function.
In future studies, Kanoski and the researchers hope to determine if changing habits, such as eating a healthier diet or increasing exercise, can reverse the harm to memory caused by elevated sugar consumption earlier in life.
Harvard University researchers have identified the biological mechanism of how chronic stress impairs hair follicle stem cells, confirming long-standing observations that stress might lead to hair loss.
In a mouse study published in the journal Nature, the researchers found that a major stress hormone causes hair follicle stem cells to stay in an extended resting phase, without regenerating the hair follicle and hair. The researchers identified the specific cell type and molecule responsible for relaying the stress signal to the stem cells, and showed that this pathway can be potentially targeted to restore hair growth.
"My lab is interested in understanding how stress affects stem cell biology and tissue biology, spurred in part by the fact that everyone has a story to share about what happens to their skin and hair when they are stressed. I realized that as a skin stem cell biologist, I could not provide a satisfying answer regarding if stress indeed has an impact -- and more importantly, if yes, what are the mechanisms," said Ya-Chieh Hsu, Ph.D., the Alvin and Esta Star Associate Professor of Stem Cell and Regenerative Biology at Harvard and senior author of the study. "The skin offers a tractable and accessible system to study this important problem in depth, and in this work, we found that stress does actually delay stem cell activation and fundamentally changes how frequently hair follicle stem cells regenerate tissues."
The hair follicle is one of the few mammalian tissues that can undergo rounds of regeneration throughout life, and has become a paradigm that informs much of our fundamental understanding of mammalian stem cell biology. The hair follicle naturally cycles between growth and rest, a process fueled by hair follicle stem cells. During the growth phase, hair follicle stem cells become activated to regenerate the hair follicle and hair, and hairs grow longer each day. During the resting phase, the stem cells are quiescent and hairs can shed more easily. Hair loss can occur if the hairs shed and the stem cells remain quiescent without regenerating new tissue.
The researchers studied a mouse model of chronic stress and found that hair follicle stem cells stayed in a resting phase for a very long time without regenerating tissues. A major stress hormone produced by the adrenal glands, corticosterone, was upregulated by chronic stress; providing corticosterone to mice was able to reproduce the stress effect on the stem cells. The equivalent hormone in humans is cortisol, which is also upregulated under stress and is often referred to as the "stress hormone."
"This result suggests that elevated stress hormones indeed have a negative effect on hair follicle stem cells," Hsu said. "But the real surprise came when we took out the source of the stress hormones."
Under normal conditions, hair follicle regeneration slows over time -- the resting phase becomes longer as the animals age. But when the researchers removed the stress hormones, the stem cells' resting phase became extremely short and the mice constantly entered the growth phase to regenerate hair follicles throughout their life, even when they were old.
"So even the baseline level of stress hormone that's normally circulating in the body is an important regulator of the resting phase. Stress essentially just elevates this preexisting 'adrenal gland-hair follicle axis,' making it even more difficult for hair follicle stem cells to enter the growth phase to regenerate new hair follicles," Hsu said.
After establishing the link between the stress hormone and hair follicle stem cell activity, the researchers looked for the biological mechanism underlying the connection.
"We first asked whether the stress hormone was regulating the stem cells directly and checked by taking out the receptor for corticosterone, but this turned out to be wrong. Instead, we found that the stress hormone actually acts on a cluster of dermal cells underneath the hair follicle, known as the dermal papilla," said Sekyu Choi, Ph.D., the lead author of the study.
Dermal papilla is known to be critical for activating hair follicle stem cells, but none of the previously identified factors secreted from dermal papilla changed when stress hormone levels were altered. Rather, the stress hormone prevented dermal papilla cells from secreting Gas6, a molecule that the researchers showed can activate the hair follicle stem cells.
"Under both normal and stress conditions, adding Gas6 was sufficient to activate hair follicle stem cells that were in the resting phase and to promote hair growth," Choi said. "In the future, the Gas6 pathway could be exploited for its potential in activating stem cells to promote hair growth. It will also be very interesting to explore if other stress-related tissue changes are related to the stress hormone's impact on regulating Gas6."
These initial findings in mice need to be further studied before they can be safely applied to humans. Harvard's Office of Technology Development has protected the intellectual property relating to this work and is exploring opportunities for collaboration on its further development and eventual commercialization.
Last year, Hsu's group discovered how stress affects another type of stem cell located in the hair follicle, the melanocyte stem cells that regenerate hair pigment. The researchers found that stress activates the sympathetic nervous system and depletes melanocyte stem cells, leading to premature hair graying. Now with the new study, the two findings together demonstrate that although stress has detrimental impacts on both hair follicle stem cells and melanocyte stem cells, the mechanisms are different. Stress depletes melanocyte stem cells directly via nerve-derived signals, while stress prevents hair follicle stem cells from making new hairs indirectly via an adrenal-gland-derived stress hormone's impact on the niche. Because hair follicle stem cells are not depleted, it might be possible to reactivate stem cells under stress with mechanisms such as the Gas6 pathway.
Beyond the potential application of the Gas6 pathway in promoting hair growth, the study's results also have broader implications for stem cell biology.
"When looking for factors that control stem cell behaviors, normally we would look locally in the skin. While there are important local factors, our findings suggest that the major switch for hair follicle stem cell activity is actually far away in the adrenal gland and it works by changing the threshold required for stem cell activation," Hsu said. "You can have systemic control of stem cell behavior located in a different organ that plays a really important role, and we are learning more and more examples of these 'cross-organ interactions.' Tissue biology is interconnected with body physiology. We still have so much to learn in this area, but we are constantly reminded by our findings that in order to understand stem cells in the skin, we often need to think beyond the skin."
Increased consumption of flavanols - a group of molecules occurring naturally in fruit and vegetables - could protect people from mental stress-induced cardiovascular events such as stroke, heart disease and thrombosis, according to new research.
Researchers have discovered that blood vessels were able to function better during mental stress when people were given a cocoa drink containing high levels of flavanols than when drinking a non-flavanol enriched drink.
A thin membrane of cells lining the heart and blood vessels, when functioning efficiently the endothelium helps to reduce the risk of peripheral vascular disease, stroke, heart disease, diabetes, kidney failure, tumour growth, thrombosis, and severe viral infectious diseases. We know that mental stress can have a negative effect on blood vessel function.
A UK research team from the University of Birmingham examined the effects of cocoa flavanols on stress-induced changes on vascular function - publishing their findings in Nutrients.
Lead author, Dr. Catarina Rendeiro, of the University of Birmingham's School of Sport, Exercise and Rehabilitation Sciences, explains: "We found that drinking flavanol-rich cocoa can be an effective dietary strategy to reduce temporary impairments in endothelial function following mental stress and also improve blood flow during stressful episodes".
"Flavanols are extremely common in a wide range of fruit and vegetables. By utilizing the known cardiovascular benefits of these compounds during periods of acute vascular vulnerability (such as stress) we can offer improved guidance to people about how to make the most of their dietary choices during stressful periods."
In a randomized study, conducted by postgraduate student Rosalind Baynham, a group of healthy men drank a high-flavanol cocoa beverage 90 minutes before completing an eight-minute mental stress task.
The researchers measured forearm blood flow and cardiovascular activity at rest and during stress and assessed functioning of the blood vessels up to 90 min post stress - discovering that blood vessel function was less impaired when the participants drank high-flavanol cocoa. The researchers also discovered that flavanols improve blood flow during stress.
Stress is highly prevalent in today's society and has been linked with both psychological and physical health. Mental stress induces immediate increases in heart rate and blood pressure (BP) in healthy adults and also results in temporary impairments in the function of arteries even after the episode of stress has ceased.
Single episodes of stress have been shown to increase the risk of acute cardiovascular events and the impact of stress on the blood vessels has been suggested to contribute to these stress-induced cardiovascular events. Indeed, previous research by Dr Jet Veldhuijzen van Zanten, co-investigator on this study, has shown that people at risk for cardiovascular disease show poorer vascular responses to acute stress.
"Our findings are significant for everyday diet, given that the daily dosage administered could be achieved by consuming a variety of foods rich in flavanols - particularly apples, black grapes, blackberries, cherries, raspberries, pears, pulses, green tea and unprocessed cocoa. This has important implications for measures to protect the blood vessels of those individuals who are more vulnerable to the effects of mental stress," commented Dr. Rendeiro.
Adding the nutrient selenium to diets protects against obesity and provides metabolic benefits to mice, according to a study published today ineLife.
The results could lead to interventions that reproduce many of the anti-aging effects associated with dietary restriction while also allowing people to eat as normal.
Several types of diet have been shown to increase healthspan -- that is, the period of healthy lifespan. One of the proven methods of increasing healthspan in many organisms, including non-human mammals, is to restrict dietary intake of an amino acid called methionine.
Recent studies have suggested that the effects of methionine restriction on healthspan are likely to be conserved in humans. Although it might be feasible for some people to practice methionine restriction, for example, by adhering to a vegan diet, such a diet might not be practical or desirable for everyone. In the current study, a research team from the Orentreich Foundation for the Advancement of Science (OFAS), Cold Spring, New York, US, aimed to develop an intervention that produces the same effects as methionine restriction, while also allowing an individual to eat a normal, unrestricted diet.
An important clue for developing such a treatment is that methionine restriction causes a decrease in the amounts of an energy-regulating hormone called IGF-1. If a treatment could be found that causes a similar decrease in IGF-1, this might also have beneficial effects on healthspan. Previous research has shown that selenium supplementation reduces the levels of circulating IGF-1 in rats, suggesting that this could be an ideal candidate.
The team first studied whether selenium supplementation offered the same protection against obesity as methionine restriction. They fed young male and older female mice one of three high-fat diets: a control diet containing typical amounts of methionine, a methionine-restricted diet, and a diet containing typical amounts of methionine as well as a source of selenium. For both male and female mice of any age, the authors found that selenium supplementation completely protected against the dramatic weight gain and fat accumulation seen in mice fed the control diet, and to the same extent as restricting methionine.
Next, they explored the effects of the three diets on physiological changes normally associated with methionine restriction. To do this, they measured the amounts of four metabolic markers in blood samples from the previously treated mice. As hoped, they found dramatically reduced levels of IGF-1 in both male and female mice. They also saw reductions in the levels of the hormone leptin, which controls food intake and energy expenditure. Their results indicate that selenium supplementation produces most, if not all, of the hallmarks of methionine restriction, which suggests that this intervention may have a similar positive effect on healthspan.
To gain insight into the beneficial effects of selenium supplementation, the researchers used a different organism -- yeast. The two most widely used measurements of healthspan in yeast are chronological lifespan, which tells us how long dormant yeast remain viable, and replicative lifespan, which measures the number of times a yeast cell can produce new offspring. The team previously showed that methionine restriction increases the chronological lifespan of yeast, so they tested whether selenium supplementation might do the same. As it turned out, yeast grown under selenium-supplemented conditions had a 62% longer chronological lifespan (from 13 days to 21 days) and a replicative lifespan extended by nine generations as compared with controls. This demonstrates that supplementing yeast with selenium produces benefits to healthspan detectable by multiple tests of cell aging.
"One of the major goals of aging research is to identify simple interventions that promote human healthspan," notes senior author Jay Johnson, Senior Scientist at OFAS. "Here we present evidence that short-term administration of either organic or inorganic sources of selenium provides multiple health benefits to mice, the most notable of which being the prevention of diet-induced obesity. In the long term, we expect that supplementation with these compounds will also prevent age-related disease and extend the overall survival of mice. It is our hope that many of the benefits observed for mice will also hold true for humans."
IMAGE: PHYSICAL ACTIVITY IS IMPORTANT IN PREVENTING HEART AND BLOOD VESSEL DISEASE IN YOUNG PEOPLE SO LONG AS THEY DON'T UNDERTAKE VERY STRENUOUS ACTIVITY ON DAYS WHEN AIR POLLUTION LEVELS ARE... view more
CREDIT: EUROPEAN HEART JOURNAL
Physical activity is important in preventing heart and blood vessel disease in young people so long as they don't undertake very strenuous activity on days when air pollution levels are high, according to a nationwide study of nearly 1.5 million people published today (Tuesday) in the European Heart Journal [1].
Until now, little has been known about the trade-offs between the health benefits of physical activity taking place outdoors and the potentially harmful effects of air pollution. Previous research by the authors of the current study had investigated the question in middle-aged people at a single point in time, but this is the first time that it has been investigated in people aged between 20-39 years over a period of several years. In addition, the researchers wanted to see what happens when people increase or decrease their physical activity over time.
The researchers from Seoul National University College of Medicine (South Korea), led by Professor Sang Min Park, looked at information from the National Health Insurance Service (NHIS) in South Korea for 1,469,972 young Koreans living in cities, who underwent two consecutive health examinations during two screening periods: 2009-2010 and 2011-2012. They followed up the participants from January 2013 to December 2018.
At each health check-up the participants completed a questionnaire asking about their physical activity in the past seven days and this information was converted into units of metabolic equivalent task (MET) minutes per week (MET-mins/week). The participants were divided into four groups: 0, 1-499, 500-999 and 1000 or more MET-mins/week. European Society of Cardiology guidelines recommend people should try to do 500-999 MET-mins/week and this can be achieved by, for example, running, cycling or hiking for 15-30 minutes five times a week, or brisk walking, doubles tennis or slow cycling for 30-60 minutes five times a week. [2]
The researchers used data from the National Ambient Air Monitoring System in South Korea to calculate annual average levels of air pollution, in particular the levels of small particulate matter that are less than or equal to 10 or 2.5 microns in diameter, known as PM10 and PM2.5 [3]. The amount of exposure to air pollution was categorised at two levels: low to moderate (less than 49.92 and 26.43 micrograms per cubic metre, μm/m3, for PM10 and PM2.5 respectively), and high (49.92 and 26.46 μm/m3 or more, respectively). [3]
Dr Seong Rae Kim, first author of the paper, said: "We found that in young adults aged 20-39 years old, the risk of cardiovascular diseases, such as stroke and heart attack, increased as the amount of physical activity decreased between the two screening periods in the group with low levels of exposure to air pollution.
"However, in the group with high levels of exposure to air pollution, increasing the amount of physical activity to more than 1000 MET-min/week, which is more than internationally recommended levels for physical activity, could adversely affect cardiovascular health. This is an important result suggesting that, unlike middle-aged people over 40, excessive physical activity may not always be beneficial for cardiovascular health in younger adults when they are exposed to high concentrations of air pollution."
He continued: "Ultimately, it is imperative that air pollution is improved at the national level in order to maximise the health benefits of exercising in young adults. These are people who tend to engage in physical activity more than other age groups while their physical ability is at its best. If air quality is not improved, this could result in the incidence of cardiovascular diseases actually increasing despite the health benefits gained from exercise."
The researchers adjusted their results to take account of factors that could affect them, such as age, sex, household income, body mass index, smoking and alcohol consumption. During the follow-up period there were 8706 cardiovascular events. Among people exposed to high levels of PM2.5 air pollution, those who increased their exercise from 0 to 1000 MET-min/week or more between the two screening periods had a 33% increased risk of cardiovascular disease during the follow-up period compared to those who were physically inactive and did not increase their exercise, although this result was slightly weaker than that needed to achieve statistical significance. This means an extra 108 people per 10,000 might develop cardiovascular disease during the follow-up period.
Among people exposed to low to moderate levels of PM2.5, those who increased their physical activity from none to 1000 MET-min/week or more had a 27% reduced risk of developing cardiovascular disease compared to those who remained inactive, although this result was also not quite statistically significant. This means 49 fewer people per 10,000 might develop cardiovascular disease during the follow-up period.
Dr Kim said: "These results are very close to statistical significance. In fact, a further analysis presented in Figures 2 and 3 of our paper shows that statistical significance was achieved for increasing and decreasing amounts of physical activity."
For low to moderate levels of PM10 air pollution, there was a statistically significant 38% or 22% increased risk of cardiovascular disease among people who started off doing 1000 MET-min/week or more and then reduced their activity to none or to 1-499 MET min/week, respectively, compared to people who maintained the same high level of activity. These results were statistically significant and mean that 74 and 66 extra people per 10,000 respectively would develop cardiovascular problems during the follow-up period.
Professor Sang Min Park, who led the research, said: "Overall, our results show that physical activity, particularly at the level recommended by European Society of Cardiology guidelines, is associated with a lower risk of developing heart and blood vessel disease among young adults. However, when air pollution levels are high, exercising beyond the recommended amount may offset or even reverse the beneficial effects."
The study cannot show that air pollution causes the increased cardiovascular risk, only that it is associated with it. Other limitations are that there was no information on whether or not the exercise took place indoors or outdoors; participants may not have remembered correctly the amount of exercise they took in the seven days before they attended their screening interview, although this is unlikely; PM2.5 data were only measured in three major cities; and the researchers did not investigate the short-term effects of exposure to air pollution.
Among patients who return to work after a heart attack, those who work more than 55 hours per week, compared to those working an average full-time job of 35-40 hours a week, increase their odds of having a second heart attack by about twofold, according to a prospective cohort study published today in the Journal of the American College of Cardiology.
Data from the International Labour Office estimates 1 in 5 workers worldwide work over 48 hours per week. Previous studies have found an association between working long hours and increased risk of coronary heart disease and stroke. This is the first study of its kind to examine the effect of long working hours and the risk of a second cardiovascular event among patients who return to work after a first heart attack.
The study recruited 967 patients from 30 hospitals across Quebec, Canada, between 1995 and 1997. Patients had a history of heart attack, were younger than 60 years of age, held a paying job within the year prior to their heart attack and planned to return to work. Follow-up interviews and questionnaires were conducted across the next six years to assess hospital readmission rates, coronary heart disease events and lifestyle risk factors, physical or chemical exposures at work (smoking, chemicals, pollution, noise, excessive heat or cold, and physical exertion), work environment and total weekly working hours.
Based on their total weekly working hours, individual participants were placed into four categories: 1) part-time (21-34 hours/week), 2) full-time (35-40 hours/week), 3) low overtime (41-54 hours/week) and 4) medium/high overtime (>55 hours/week).
Using an assessment questionnaire, the researchers measured levels of stressful work through job strain. If a participant had high psychological demands at work (quantity of work, time constraints and level of intellectual effort required) and low decision control (opportunities for learning, autonomy and participation in the decision-making process), they were classified as having job strain. In addition, social support in and out of work were measured.
During the study period, 21.5% of participants had a second heart attack. Working long hours was associated with an about twofold increase in the risk of a second heart attack. Men were more likely to be working medium/high overtime hours (10.7% of men vs. 1.9% of women), as well as younger workers. In addition, those with worse lifestyle risk factors (smoking, alcohol intake, physical inactivity), and who worked a more stressful job were also more likely to be in the medium/high overtime category.
"To reduce the risk of coronary heart disease recurrence, secondary prevention interventions aimed at reducing the number of working hours should be evaluated in future studies," Trudel said. "Long working hours should be assessed as part of early and subsequent routine clinical follow-up to improve the prognosis of post-heart attack patients."
In an accompanying editorial comment, Jian Li, MD, PhD, a professor in the Fielding School of Public Health and School of Nursing at University of California, Los Angeles, said the study results have important implications for clinical practice, such as more comprehensive measures for secondary prevention for heart attack patients.
"The study provides a new piece of research evidence that work-related factors play an important role in coronary heart disease prognosis," Li said. "Occupational health services are urgently needed to be incorporated into secondary prevention of cardiovascular disease."
This study has several limitations, including a small sample size of women participants and an assessment of long working hours at baseline only. Future studies, with larger sample size, should look at the effect of cumulative exposure.
The recommendations are clear: physical activity is good for mental health. But it also depends on how varied it is. That's what a new study by researchers at the University of Basel shows, pointing to one of the reasons why well-being suffers during the pandemic.
A walk in the morning, a jog in the evening or even just going out to buy groceries: activity helps the psyche. Many are trying to stay active during the pandemic despite mandatory home office and limited leisure activities. Others find that they are moving significantly less than before the pandemic because previous everyday activities are off-limits due to measures taken against the spread of Covid-19.
Against this backdrop, a study led by Professor Andrew Gloster of the University of Basel provides an indication of what impact restricted movement patterns might have. The results have been published in the journal BMC Psychiatry.
That exercise promotes not only physical but also mental health is known from various studies. However, these mostly focused on the influence of deliberate exercise programs. "In contrast, little was known about whether everyday, naturally chosen movement patterns also influence mental health," Gloster explains.
To investigate this, he and researchers at the University Psychiatric Clinics in Basel collected GPS data from 106 patients with mental disorders who agreed to participate. For this purpose, the study participants were given extra smartphones that they carried with them for a week. This allowed the researchers to track their movements without interfering with the patients' daily routine. The research team then compared the movement data with surveys of the participants' well-being and symptoms of their mental illness.
The results showed that the more people moved and the more varied their movements, the greater their sense of well-being. However, no influence on the symptoms could be determined. "Our results suggest that activity alone is not enough to reduce symptoms of mental disorders, but can at least improve subjective well-being," Gloster elaborates.
"Although the data were collected before the pandemic, the results are also relevant in light of the limitations during the coronavirus crisis," he adds. Because many social and recreational activities were discontinued during that time, many people's physical activity patterns also likely became more monotonous. Various studies by research groups at the University of Basel have been able to show that the pandemic took a toll on the psyche of the population. The results of the team led by Gloster suggest that the restricted movement patterns could also play a role in this.
