Long working hours increasing deaths from heart disease and stroke: WHO, ILO

Long working hours led to 745 000 deaths from stroke and ischemic heart disease in 2016, a 29 per cent increase since 2000, according to the latest estimates by the World Health Organization and the International Labour Organization published in Environment International.  

In a first global analysis of the loss of life and health associated with working long hours, WHO and ILO estimate that, in 2016, 398 000 people died from stroke and 347 000 from heart disease as a result of having worked at least 55 hours a week. Between 2000 and 2016, the number of deaths from heart disease due to working long hours increased by 42%, and from stroke by 19%.

This work-related disease burden is particularly significant in men (72% of deaths occurred among males), people living in the Western Pacific and South-East Asia regions, and middle-aged or older workers. Most of the deaths recorded were among people dying aged 60-79 years, who had worked for 55 hours or more per week between the ages of 45 and 74 years.

With working long hours now known to be responsible for about one-third of the total estimated work-related burden of disease, it is established as the risk factor with the largest occupational disease burden. This shifts thinking towards a relatively new and more psychosocial occupational risk factor to human health.

The study concludes that working 55 or more hours per week is associated with an estimated 35% higher risk of a stroke and a 17% higher risk of dying from ischemic heart disease, compared to working 35-40 hours a week.

Further, the number of people working long hours is increasing, and currently stands at 9% of the total population globally.  This trend puts even more people at risk of work-related disability and early death.

The new analysis comes as the COVID-19 pandemic shines a spotlight on managing working hours; the pandemic is accelerating developments that could feed the trend towards increased working time.

“The COVID-19 pandemic has significantly changed the way many people work,“ said Dr Tedros Adhanom Ghebreyesus, WHO Director-General. “Teleworking has become the norm in many industries, often blurring the boundaries between home and work. In addition, many businesses have been forced to scale back or shut down operations to save money, and people who are still on the payroll end up working longer hours. No job is worth the risk of stroke or heart disease. Governments, employers and workers need to work together to agree on limits to protect the health of workers.”

NIH study links cigarette smoking to higher stroke risk in African Americans

African Americans who smoke are nearly 2.5 times more likely to have a stroke than those who never smoked, while former smokers show a similarly lower risk as never smokers, according to a new study funded by the National Institutes of Health.

The findings from the Jackson Heart Study suggests that even after years of smoking, African Americans — who as a group are twice as likely as whites to have a stroke and die from it — could significantly reduce their risk if they kicked the habit. The study’s findings, funded by the National Heart, Lung, and Blood Institute (NHLBI) and the National Institute for Minority Health and Health Disparities (NIMHD), both part of NIH, will appear online in the Journal of the American Heart Association(link is external).

Numerous studies have shown the link between smoking and stroke, but few have directly assessed the relationship solely in African Americans. This new study did that and also analyzed traditional risk factors for cardiovascular diseases and inflammation.

“This study provides further strong evidence of the link between cigarette smoking and stroke in African Americans,” said David Goff, M.D., Ph.D., director of the Division of Cardiovascular Sciences at NHLBI. “We know that quitting smoking is one way to lower the risk for stroke, which is particularly important for the most vulnerable populations during this pandemic.”

The study included 4,410 black men and women without a history of stroke and who were enrolled in the Jackson Heart Study, the largest study of cardiovascular disease in African Americans. Researchers classified the participants, who were 54 on average, into three groups based on their self-reported smoking history: current smokers, past smokers who smoked at least 400 cigarettes in their lifetimes, and never smokers.

The researchers further classified current smokers based on smoking intensity. One group included participants who smoked up to 19 cigarettes a day; another included those who smoked 20 or more cigarettes a day. Researchers followed participants from their initial evaluations beginning in 2000 through 2015.

At its start, the study included 781 past smokers, 546 current smokers, and 3,083 never smokers. By 2015, 5.2% of past smokers, 6.6% of those were smoking up to 19 cigarettes a day, and 7.2% of those smokers smoking more than 20 cigarettes a day had experienced a stroke, compared to 3.4% of never smokers.

After accounting for multiple risk factors for stroke, such as high blood pressure, diabetes, high “bad” cholesterol levels, and older age, researchers calculated that current smokers carried a risk for stroke that was more than double the risk for never smokers. And, the risk nearly tripled for those smoking 20 or more cigarettes each day. But past smokers showed an almost identical risk as never smokers.

“The bottom line is the more a person smokes, the greater their chance is of having a stroke,” said Adebamike A. Oshunbade, M.D., M.P.H., the lead study author and postdoctoral research fellow at the University of Mississippi Medical Center. “It’s important to communicate this risk to vulnerable populations, especially with the growing popularity of new tobacco products.”

Michael E. Hall, M.D., associate professor of medicine at the University of Mississippi Medical Center, Jackson, and corresponding study author, agreed. He noted that while smoking has been shown in major studies to raise the risk of stroke 1.5 times for the general population, “these adverse health effects seem to be magnified in African Americans.”

In their analysis, the researchers also looked more closely at the already-established link between inflammation and atherosclerosis and smoking. They measured for C-reactive protein (CRP), a marker of inflammation, and carotid intima-media thickness, or CIMT, to assess the buildup of fatty plaques in the carotid arteries that supply blood to the brain.

The researchers found that African American smokers who smoked 20 or more cigarettes a day had higher CIMT compared to never smokers. Researchers said this suggests that the buildup of plaque in the major blood vessels of the brains of African American smokers could play a role in the development of stroke.

NIH scientists identify spasm in women with endometriosis-associated chronic pelvic pain

Small study suggests botulinum toxin may be potential treatment.

Pelvic pain associated with endometriosis often becomes chronic and can persist (or recur) following surgical and hormonal interventions. According to results published in Regional Anesthesia & Pain Medicine, treating pelvic floor muscle spasm with botulinum toxin may relieve pain and improve quality of life.

Woman holding her back due to lower back spasm. Photo credit: Medical News Today

The study was conducted by scientists at the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health. 

“The botulinum toxin injections were incredibly effective in decreasing pain levels, as well as patients’ use of pain medications, including opioids,” said Pamela Stratton, M.D., a gynecologist and scientist at NINDS, who co-led the study with Barbara Karp, M.D., a neurologist and program director at NINDS. “Many of the women in our study reported that the pain had a profound effect on their quality of life, and this treatment may be able to help them get their lives back.”

Endometriosis occurs when the uterine tissue lining grows outside of the uterus and is estimated to affect up to 176 million women worldwide. It is an inflammatory condition that can lead to infertility and cause chronic pain. The usual gynecologic treatments include hormonal therapy and surgery to remove the growths. However, in many cases, pain returns after the interventions.

In the study, women with surgically treated endometriosis who were generally taking hormones to suppress menses, but who continued to experience pain and had pelvic floor muscle spasm, initially received injections of botulinum toxin or saline as part of a placebo-controlled clinical trial, targeting areas of spasm. At least one month after the masked study injection, 13 participants chose to receive open-label botulinum toxin injections in areas that remained in spasm and were then followed for at least four months. These patients were described in the current study at the NIH Clinical Center. 

In all participants, during follow-up, pelvic floor muscle spasm was not detected or occurred in fewer muscles. Within two months of receiving the injections, pain decreased in all of the participants, with 11 out of 13 subjects reporting that their pain was mild or had disappeared. Additionally, usage of pain medication was reduced in more than half of the participants. Prior to receiving toxin injections, eight participants reported moderate or severe disability and after treatment, six of those patients noted an improvement.

The participants experienced a decrease in muscle spasm and had pain relief that resulted in less disability and less use of pain medication. These findings suggest that pelvic floor muscle spasm may be experienced by women with endometriosis and contribute to pain persisting after standard treatment. Importantly, the beneficial effects were long-lasting, with many patients reporting pain relief lasting at least six months. 

Botulinum toxins, such as Botox, work by blocking the nerve signals for muscles to contract and have been used to treat migraines and certain movement disorders. Previous research has suggested that botulinum toxin may help women experiencing other types of chronic pelvic pain, but this treatment had not been studied in women with endometriosis.

“We know that many doctors are using botulinum toxin to help their patients, but everyone uses slightly different techniques and methods, including different brands of toxin and various doses. This study will begin to provide rigor to help ensure standardized protocols and treatment in pelvic pain,” said Dr. Karp.

Larger clinical studies will need to confirm the current findings. In addition, future research will focus on the mechanisms underlying chronic pelvic pain and better understanding of ways in which botulinum toxin may help treat those disorders.

The NINDS is the nation’s leading funder of research on the brain and nervous system. The mission of NINDS is to seek fundamental knowledge about the brain and nervous system and to use that knowledge to reduce the burden of neurological disease.

Gut bacteria may control movement

NIH-funded study suggests that bacteria may regulate neuronal circuits behind movement in flies.

A new study puts a fresh spin on what it means to “go with your gut.” The findings, published in Nature, suggest that gut bacteria may control movement in fruit flies and identify the neurons involved in this response. The study was supported by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health.

“This study provides additional evidence for a connection between the gut and the brain, and in particular outlines how gut bacteria may influence behavior, including movement,” said Margaret Sutherland, Ph.D., program director at NINDS.

Researchers led by Sarkis K. Mazmanian, Ph.D., professor of microbiology at the California Institute of Technology in Pasadena, and graduate student Catherine E. Schretter, observed that germ-free flies, which did not carry bacteria, were hyperactive. For instance, they walked faster, over greater distances, and took shorter rests than flies that had normal levels of microbes. Dr. Mazmanian and his team investigated ways in which gut bacteria may affect behavior in fruit flies.

“Locomotion is important for a number of activities such as mating and searching for food. It turns out that gut bacteria may be critical for fundamental behaviors in animals,” said Dr. Mazmanian.

Fruit flies carry between five and 20 different species of bacteria and Dr. Mazmanian’s team treated the germ-free animals with individual strains of those microbes. When the flies received Lactobacillus brevis, their movements slowed down to normal speed. L. brevis was one of only two species of bacteria that restored normal behavior in the germ-free flies.

Dr. Mazmanian’s group also discovered that the molecule xylose isomerase (Xi), a protein that breaks down sugar and is found in L. brevis, may be critical to this process. Isolating the molecule and treating germ-free flies with it was sufficient to slow down the speedwalkers.

Additional experiments showed that Xi may regulate movement by fine-tuning levels of certain carbohydrates, such as trehalose, which is the main sugar found in flies and is similar to mammalian glucose. Flies that were given Xi had lower levels of trehalose than did untreated germ-free flies. When Xi-treated flies, which showed normal behavior, were given trehalose alone, they resumed fast movements suggesting that the sugar was able to reverse the effects of Xi.

Next, the researchers looked into the flies’ nervous system to see what cells were involved in bacteria-directed movement. When Dr. Mazmanian’s team turned on neurons that produce the chemical octopamine, that activation canceled out the effect of L. brevis on the germ-free flies. As a result, the flies, which had previously slowed down after receiving the bacterium or Xi, resumed their speedwalking behavior. Turning on octopamine-producing nerve cells in flies with normal levels of bacteria also caused them to move faster. However, activating neurons that produce other brain chemicals did not influence the flies’ movements.

According to Dr. Mazmanian, Schretter and their colleagues, Xi may be monitoring the flies’ metabolic state, including levels of nutrients, and then signaling to octopamine neurons whether they should turn on or off, resulting in changes in behavior.

Instead of octopamine, mammals produce a comparable chemical called noradrenaline, which has been shown to control movement.

“Gut bacteria may play a similar role in mammalian locomotion, and even in movement disorders such as Parkinson’s disease,” said Dr. Mazmanian.

More research is needed to see whether bacteria control movement in other species, including mammals. In addition, future studies will further investigate how Xi is involved in these behaviors.

NIH study broadens understanding of High Impact Chronic Pain in the U.S.

Researchers have demonstrated that disability is as likely in the chronic pain population as it is in those with kidney failure, emphysema or stroke.

This is the reality for 11 million U.S. adults with High Impact Chronic Pain (HICP), a new concept that describes those with pain lasting three months or longer and accompanied by at least one major activity restriction.

These findings directly address recommendations suggested in the National Pain Strategy by more accurately characterizing the HICP population to further understanding of chronic pain. This study — conducted by scientists at the National Center for Complementary and Integrative Health (NCCIH) and the National Institute of Neurological Disorders and Stroke (NINDS) at the National Institutes of Health as well as the Kaiser Permanente Washington Health Research Institute, Seattle,— was published in the Journal of Pain.

“The multidimensional nature of chronic pain is not reflected in commonly used operational definitions based solely on pain duration, resulting in inordinately high prevalence estimates that limit our ability to effectively address chronic pain on a national level,” said Mark Pitcher, Ph.D., visiting fellow in the Division of Intramural Research at NCCIH and one of the authors of the study.

Among the study’s top findings was the revelation that pain-related disability identifies a substantial portion of the chronic pain population experiencing progressive deterioration in mental and physical health outcomes along with substantially higher health care usage. Together, the HICP population constitutes some 4.8 percent of the U.S. adult population. About 83 percent of people with HICP were unable to work for a living, and one-third had difficulty with self-care activities such as washing themselves and getting dressed.

“By differentiating those with HICP, a condition that is associated with higher levels of anxiety, depression, fatigue, and cognitive difficulty, we hope to improve clinical research and practice,” said M. Catherine Bushnell, Ph.D., scientific director in the NCCIH Division of Intramural Research and another author of the study.

The concept of HICP was first proposed by the National Pain Strategy to better identify those with significant levels of life interference. While prior epidemiological surveys have assessed the impact of pain using questions that ask how much pain interferes with life activities, it is likely that individuals with severe pain may have had difficulty distinguishing the increased effort required to carry out important life activities. As such, this study used an alternative approach to untether the pain experience from its impact. Activity limitations and participation restrictions were assessed using general disability questions without reference to pain experience.

“It is crucial that we fully understand how people’s lives are affected by chronic pain. It will help improve care for individuals living with chronic pain and strategically guide our research programs that aim to reduce the burden of pain at the population level,” said Linda Porter, Ph.D., director of the Office of Pain Policy at NINDS. “The findings from this study are a strong step toward these goals.”

The study employed nationally representative data from the 2011 National Health Interview Survey to assess the prevalence, psychosocial characteristics, health status and health care usage of the chronic pain population. The study also determined the degree of contribution made by other chronic health conditions to activity limitations and participation restrictions. Statistical analyses were performed on merged datasets that represented a weighted population size of approximately 220.3 million non-institutionalized adults.

This study ultimately highlights the role of pain-related disability as a key indicator of pain impact. Its findings not only serve to refine clinical research and streamline treatment, they also provide much-needed information to policymakers. As such, the results are relevant to researchers, health care professionals and legislators interested in shaping policy around a global health issue.

This study was partially supported by the Intramural Research Programs at the NIH’s NCCIH and NINDS.

Eye could provide “window to the brain” after stroke

Eyes yield information about strokes: MRI scans revealed that a chemical called gadolinium, used to improve images, leaked into the eyes of stroke patients.NINDS Stroke Branch

Research into curious bright spots in the eyes on stroke patients’ brain images could one day alter the way these individuals are assessed and treated. A team of scientists at the National Institutes of Health found that a chemical routinely given to stroke patients undergoing brain scans can leak into their eyes, highlighting those areas and potentially providing insight into their strokes. The study was published in Neurology.

“We were kind of astounded by this – it’s a very unrecognized phenomenon,” said Richard Leigh, M.D., an assistant clinical investigator at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and the paper’s senior author. “It raises the question of whether there is something we can observe in the eye that would help clinicians evaluate the severity of a stroke and guide us on how best to help patients.”

The eyes glowed so brightly on those images due to gadolinium, a harmless, transparent chemical often given to patients during magnetic resonance imaging (MRI) scans to highlight abnormalities in the brain. In healthy individuals, gadolinium remains in the blood stream and is filtered out by the kidneys. However, when someone has experienced damage to the blood-brain barrier, which controls whether substances in the blood can enter the brain, gadolinium leaks into the brain, creating bright spots that mark the location of brain damage.

Previous research had shown that certain eye diseases could cause a similar disruption to the blood-ocular barrier, which does for the eye what the blood-brain barrier does for the brain. Dr. Leigh’s team discovered that a stroke can also compromise the blood-ocular barrier and that the gadolinium that leaked into a patient’s eyes could provide information about his or her stroke.

“It looks like the stroke is influencing the eye, and so the eye is reflective of what is going on in the brain,” Dr. Leigh said. “Clearly these results are preliminary, so future studies will have to be attuned to this to fully understand its impact.”

The researchers performed MRI scans on 167 stroke patients upon admission to the hospital without administering gadolinium and compared them to scans taken using gadolinium two hours and 24 hours later. Because gadolinium is transparent, it did not affect patients’ vision and could only be detected with MRI scans. Roughly three-quarters of the patients experienced gadolinium leakage into their eyes on one of the scans, with 66 percent showing it on the two-hour scan and 75 percent on the 24-hour scan. The phenomenon was present in both untreated patients and patients who received a treatment, called tPA, to dissolve the blood clot responsible for their strokes.

Gadolinium was typically present in the front part of the eye, called the aqueous chamber, after two hours, and in a region towards the back, called the vitreous chamber, after 24 hours. Patients showing gadolinium in the vitreous chamber at the later timepoint tended to be of older age, have a history of hypertension, and have more bright spots on their brain scans, called white matter hyperintensities, that are associated with brain aging and decreased cognitive function.

In a minority of patients, the two-hour scan showed gadolinium in both eye chambers. The strokes in those patients tended to affect a larger portion of the brain and cause even more damage to the blood-brain barrier than the strokes of patients with a slower pattern of gadolinium leakage or no leakage at all. The findings raise the possibility that, in the future, clinicians could administer a substance to patients that would collect in the eye just like gadolinium and quickly yield important information about their strokes without the need for an MRI.

“It is much easier for us to look inside somebody’s eye than to look into somebody’s brain,” Dr. Leigh said. “So if the eye truly is a window to the brain, we can use one to learn about the other.”

Despite the relationship between gadolinium leakage and stroke severity, the phenomenon was not found to be related to the level of disability the patients developed following their strokes. It also remains unclear whether gadolinium can enter the eye in healthy people.