1. Young binge drinkers show altered brain activity

    September 23, 2017 by Ashley

    From the Frontiers press release:

    Researchers have studied the brain activity of young binge-drinking college students in Spain, and found distinctive changes in brain activity, which may indicate delayed brain development and be an early sign of brain damage.

    For many students, college involves a lot of socializing at parties and at bars, and alcohol is a common factor in these social environments. Excessive alcohol use, in the form of binge drinking, is extremely common among college students, and one study has estimated that as many as one third of young North Americans and Europeans binge drink.

    So, what defines binge drinking? The National Institute of Alcohol Abuse and Alcoholism describes a binge as drinking five or more drinks for men and four or more for women within a two-hour period, and for many college students, these limits wouldn’t equate to a particularly heavy night. Previous research has linked binge drinking to a variety of negative consequences including neurocognitive deficits, poor academic performance, and risky sexual behavior.

    While numerous studies have shown that the brains of chronic alcoholics have altered brain activity, there is also evidence that bingeing can change adolescents’ brains. Eduardo López-Caneda, of the University of Minho in Portugal, investigates this phenomenon.

    “A number of studies have assessed the effects of binge drinking in young adults during different tasks involving cognitive processes such as attention or working memory,” says López-Caneda. “However, there are hardly any studies assessing if the brains of binge drinkers show differences when they are at rest, and not focused on a task.”

    In a recent study published in Frontiers in Behavioral Neuroscience, López-Caneda and colleagues set out to see if the resting brains of binge-drinking college students showed any differences compared with those of their non-bingeing counterparts.

    The researchers recruited first year college students from a university in Spain, and asked them to complete a questionnaire about their drinking habits. Students that had participated in at least one binge within the previous month were considered to be binge drinkers, whereas non-bingers had never binged before. By attaching electrodes to the students’ scalps, the scientists could assess electrical activity in various brain regions.

    Compared with the non-bingers, the binge drinkers demonstrated altered brain activity at rest. They showed significantly higher measurements of specific electrophysiological parameters, known as beta and theta oscillations, in brain regions called the right temporal lobe and bilateral occipital cortex.

    Surprisingly, previous studies have found very similar alterations in the brains of adult chronic alcoholics. While the young bingers in this study might occasionally consume alcohol to excess, they did not fit the criteria for alcoholism. So, what does this mean?

    The changes might indicate a decreased ability to respond to external stimuli and potential difficulties in information processing capacity in young binge drinkers, and may represent some of the first signs of alcohol-induced brain damage.

    The brains of adolescents are still developing, meaning that they might be more vulnerable to the effects of alcohol abuse. “These features might be down to the particularly harmful effects of alcohol on young brains that are still in development, perhaps by delaying neuromaturational processes,” says López-Caneda.

    The researchers stress that they need to carry out further studies to confirm if the features they have observed in these young binge drinkers are caused by their bingeing, and if their brain development might be impaired. However, the results suggest that bingeing has tangible effects on the young brain, comparable with some of those seen in chronic alcoholics. “It would be a positive outcome if educational and health institutions used these results to try to reduce alcohol consumption in risky drinkers,” says López-Caneda.


  2. Study suggests sportspeople can face retirement identity crisis

    September 22, 2017 by Ashley

    From the University of Portsmouth press release:

    New research shows how top-level sportspeople can struggle to adjust to life after retirement, with their identities continuing to be defined by their former careers.

    The research, published in the journal Qualitative Research in Sport, Exercise and Health, illustrates how some athletes struggle to adjust socially and psychologically following retirement. Previous studies have shown that in the most extreme cases it can lead to depression, eating disorders and substance abuse.

    The study was led by Dr Francesca Cavallerio of Anglia Ruskin University, who worked alongside Dr Chris Wagstaff of the University of Portsmouth and Dr Ross Wadey of St Mary’s University.

    Dr Wagstaff said: “Adapting to retirement is difficult for many people in society and this is particularly the case in elite sport. Such environments are characterised by very clear social and cultural expectations. In order to be successful, athletes typically conform to and associate success with these cultural norms.

    “This study showed that, unfortunately, when athletes retire many struggle to identify with anything other than their sport, which for many, has been the principal focus of their life for many years. Therefore, sport organisations must do more to support the non-sport lives of their athletes.”

    Dr Cavallerio, a Lecturer in Sport and Exercise Sciences at Anglia Ruskin University, interviewed female gymnasts who had retired from elite-level competition and found that their stories followed one of three narratives or storylines: Entangled, Going forward and Making sense.

    For instance, some former gymnasts who were identified as entangled had their identities completely defined by their former athletic self and the values instilled in them when they competed. They struggled to adapt to life after gymnastics and suffered from low confidence, low self-esteem, and a lack of drive towards new goals and experiences.

    The going forward former athletes were able to develop different identities to that of a gymnast at the same time as they were competing at a high level. Once their gymnastics careers were over, they were able to make the most of what they had learnt in sport to help their future development.

    Those in the making sense group fell somewhere in between, not confident enough to be going forward but struggling not to remain entangled in their former life. Future experiences were likely to decide whether they would more closely follow the going forward or entangled narratives.

    Dr Cavallerio said: “Sport continues to embrace the early identification and development of talented athletes. In many sports, the age at which people begin training at a professional level is getting younger.

    “Our study shows that how athletes are treated and influenced at a young age can have an effect on how they deal with retirement.

    “The issues we observed should be of interest to clubs and governing bodies across a range of sports. On a practical level they should be encouraging young athletes to develop a non-sporting identity at the same time as a sporting identity, and have a range of interests and friendships outside of their sport.”


  3. Systems analysis points to links between Toxoplasma infection and common brain diseases

    by Ashley

    From the University of Chicago Medical Center press release:

    More than 2 billion people — nearly one out of every three humans on earth, including about 60 million people in the United States — have a lifelong infection with the brain-dwelling parasite Toxoplasma gondii.

    In the September 13, 2017, issue of Scientific Reports, 32 researchers from 16 institutions describe efforts to learn how infection with this parasite may alter, and in some cases amplify, several brain disorders, including epilepsy, Alzheimer’s and Parkinson’s diseases as well as some cancers.

    When a woman gets infected with T. gondii during pregnancy and passes the parasite on to her unborn child, the consequences can be profound, including devastating damage to the brain, nervous system and eyes.

    There is growing evidence, however, that acquiring this infection later in life may be far from harmless. So the researchers began looking for connections between this chronic but seemingly dormant infection and its potential to alter the course of common neurologic disorders.

    “We wanted to understand how this parasite, which lives in the brain, might contribute to and shed light on pathogenesis of other, brain diseases,” said Rima McLeod, MD, professor of ophthalmology & visual science and pediatrics and medical director of the Toxoplasmosis Center at the University of Chicago.

    “We suspect it involves multiple factors,” she said. “At the core is alignment of characteristics of the parasite itself, the genes it expresses in the infected brain, susceptibility genes that could limit the host’s ability to prevent infection, and genes that control susceptibility to other diseases present in the human host. Other factors may include pregnancy, stress, additional infections, and a deficient microbiome. We hypothesized that when there is confluence of these factors, disease may occur.”

    For more than a decade, researchers have noted subtle behavior manipulations associated with a latent T. gondii infection. Rats and mice that harbor this parasite, for example, lose their aversion to the smell of cat urine. This is perilous for a rodent, making it easier for cats to catch and eat them. But it benefits cats, who gain a meal, as well as the parasites, who gain a new host, who will distribute them widely into the environment. An acutely infected cat can excrete up to 500 million oocysts in a few weeks’ time. Even one oocyst, which can remain in soil or water for up to a year, is infectious.

    A more recent study found a similar connection involving primates. Infected chimpanzees lose their aversion to the scent of urine of their natural predator, leopards.

    The research team decided to search for similar effects in people. They focused on what they call the human “infectome” — plausible links between the parasite’s secreted proteins, expressed human microRNAs, the neural chemistry of the human host, and the multiple pathways that are perturbed by host-parasite interactions.

    Using data collected from the National Collaborative Chicago-Based Congenital Toxoplasmosis Study, which has diagnosed, treated and followed 246 congenitally infected persons and their families since 1981, they performed a “comprehensive systems analysis,” looking at a range of parasite-generated biomarkers and assessing their probable impact.

    Working with the J Craig Venter Institute and the Institute of Systems Biology Scientists, they looked at the effect of infections of primary neuronal stem cells from the human brain in tissue culture, focusing on gene expression and proteins perturbed. Part of the team, including Huan Ngo from Northwestern University, Hernan Lorenzi at the J Craig Venter Institute, Kai Wang and Taek-Kyun Kim at the Institute for Systems Biology and McLeod, integrated host genetics, proteomics, transcriptomics and circulating microRNA datasets to build a model of these effects on the human brain.

    Using what they called a “reconstruction and deconvolution,” approach, the researchers identified perturbed pathways associated with neurodegenerative diseases as well as connections between toxoplasmosis, human brain disorders and some cancers.

    They also found that:

    • Small regulatory biomarkers — bits of microRNA or proteins found in children with severe toxoplasmosis — matched those found in patients with neurodegenerative diseases like Alzheimer’s or Parkinson’s disease.
    • The parasite was able to manipulate 12 human olfactory receptors in ways that mimicked the cat-mouse or the chimp-leopard exchange.
    • Evidence that T. gondii could increase the risk of epilepsy, “possibly by altering GABAergic signaling.”
    • T. gondii infection was associated with a network of 1,178 human genes, many of which are modified in various cancers.

    “Our results provide insights into mechanisms whereby this parasite could cause these associated diseases under some circumstances,” the authors wrote. “This work provides a systems roadmap to design medicines and vaccines to repair and prevent neuropathological effects of T. gondii on the human brain.”

    “This study is a paradigm shifter,” said co-author Dennis Steinler, PhD, director of the Neuroscience and Aging Lab at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. “We now have to insert infectious disease into the equation of neurodegenerative diseases, epilepsy and neural cancers.”

    “At the same time,” he added, “we have to translate aspects of this study into preventive treatments that include everything from drugs to diet to life style, in order to delay disease onset and progression.”


  4. How do close relationships lead to longer life?

    September 19, 2017 by Ashley

    From the American Psychological Association press release:

    While recent research has shown that loneliness can play a role in early death, psychologists are also concerned with the mechanisms by which social relationships and close personal ties affect health. A special issue of American Psychologist, the flagship journal of the American Psychological Association, offers an overview of the science and makes the case for psychological scientists to work together to make close relationships a public health priority.

    “The articles in this special issue represent state-of-the-art work on the central issues in the study of close relationships and health. They draw from relationship science and health psychology, two areas of scientific inquiry with independent histories and distinct domains,” special issue editor Christine Dunkel Schetter, PhD, wrote in the introduction. “The goal of this special issue is to bridge the gap between these two specialties to improve the quality and usefulness of future research and practice.”

    Articles focus on topics including how healthy relationships early in life affect physical and mental health in childhood and beyond; the role of intimate relationships in coronary heart disease; the need to focus on partners when treating someone with chronic disease; and the increasingly complex biological pathways involved linking relationships to health.

    “The challenge remains to translate existing and future knowledge into interventions to improve social relationships for the benefit of physical and mental health,” wrote Dunkel Schetter, of the University of California, Los Angeles.


  5. Study suggests yoga, meditation improve brain function and energy levels

    September 18, 2017 by Ashley

    From the University of Waterloo press release:

    Practicing brief sessions of Hatha yoga and mindfulness meditation can significantly improve brain function and energy levels, according to a new study from the University of Waterloo.

    The study found that practicing just 25 minutes of Hatha yoga or mindfulness meditation per day can boost the brain’s executive functions, cognitive abilities linked to goal-directed behavior and the ability to control knee-jerk emotional responses, habitual thinking patterns and actions.

    “Hatha yoga and mindfulness meditation both focus the brain’s conscious processing power on a limited number of targets like breathing and posing, and also reduce processing of nonessential information,” said Peter Hall, associate professor in the School of Public Health & Health Systems. “These two functions might have some positive carryover effect in the near- term following the session, such that people are able to focus more easily on what they choose to attend to in everyday life.”

    Thirty-one study participants completed 25 minutes of Hatha yoga, 25 minutes of mindfulness meditation, and 25 minutes of quiet reading (a control task) in randomized order. Following both the yoga and meditation activities, participants performed significantly better on executive function tasks compared to the reading task.

    “This finding suggests that there may be something special about meditation — as opposed to the physical posing — that carries a lot of the cognitive benefits of yoga,” said Kimberley Luu, lead author on the paper.

    The study also found that mindfulness meditation and Hatha yoga were both effective for improving energy levels, but Hatha yoga had significantly more powerful effects than meditation alone.

    “There are a number of theories about why physical exercises like yoga improve energy levels and cognitive test performance,” said Luu. “These include the release of endorphins, increased blood flow to the brain, and reduced focus on ruminative thoughts. Though ultimately, it is still an open question.”

    Hatha yoga is one of the most common styles of yoga practiced in Western countries.

    It involves physical postures and breathing exercises combined with meditation. Mindfulness mediation involves observing thoughts, emotions and body sensations with openness and acceptance.

    Although the meditative aspect might be even more important than the physical posing for improving executive functions, there are additional benefits to Hatha yoga including improvements in flexibility and strength,” said Hall. “These benefits may make Hatha yoga superior to meditation alone, in terms of overall health benefits.”


  6. Study suggests cultural context may affect link between positive emotions and health

    September 14, 2017 by Ashley

    From the Association for Psychological Science press release:

    Positive emotions are often seen as critical aspects of healthy living, but new research suggests that the link between emotion and health outcomes may vary by cultural context. The findings, published in Psychological Science, a journal of the Association for Psychological Science, show that experiencing positive emotions is linked with better cardiovascular health in the US but not in Japan.

    “Our key finding is that positive emotions predict blood-lipid profiles differently across cultures,” says psychological scientist Jiah Yoo of the University of Wisconsin-Madison. “American adults who experience high levels of positive emotions, such as feeling ‘cheerful’ and ‘extremely happy’, are more likely to have healthy blood-lipid profiles, even after accounting for other factors such as age, gender, socioeconomic status, and chronic conditions. However, this was not true for Japanese adults.”

    “Our findings underscore the importance of cultural context for understanding links between emotion and health, something that has been largely ignored in the literature,” Yoo adds. “Although some studies have examined cultural differences in links between positive emotions and healthy functioning, this work is novel in that it includes biological measures of health and large representative samples from both countries.”

    The fact that positive emotions are conceived of and valued differently across cultures led Yoo and colleagues to wonder whether the health benefits observed in tandem with positive emotions might be specific to Western populations.

    In American cultures, experiencing positive emotions is seen as desirable and is even encouraged via socialization. But in East Asian cultures, people commonly view positive emotions as having dark sides — they are fleeting, may attract unnecessary attention from others, and can be a distraction from focusing on important tasks,” says Yoo.

    The researchers designed a cross-cultural comparison, examining data from two large representative studies of adults: Midlife in the United States and Midlife in Japan, both funded by the National Institute on Aging. Data included participants’ ratings of how frequently they felt 10 different positive emotions in the previous 30 days and measures of blood lipids, which provided objective data on participants’ heart health.

    “Because of the global prevalence of coronary artery disease, blood lipids are considered important indices of biological health in many Western and East Asian countries,” Yoo explains.

    As expected, the data indicated that experiencing frequent positive emotions was associated with healthy lipid profiles for American participants. But there was no evidence of such a link for Japanese participants.

    The differences may be due, in part, to the relationships between positive emotions and BMI in each culture. Higher positive emotions were linked with lower BMI and, in turn, healthier lipid profiles among American participants, but not among Japanese participants.

    “By demonstrating that the cultural variation in the connection between emotional well-being and physical well-being, our research has wide-ranging relevance among those who seek to promote well-being in the communities and the workplace, including clinicians, executives, and policy makers,” Yoo concludes.

    In future work, the researchers will examine longitudinal data to determine whether the evidence suggests a direct causal link between emotions and health. They also hope to identify emotional profiles that may be more relevant or important to health outcomes in East Asian cultures.


  7. Brain changes linked to physical, mental health in functional neurological disorder

    September 13, 2017 by Ashley

    From the Massachusetts General Hospital press release:

    An imaging study by Massachusetts General Hospital (MGH) investigators has identified differences in key brain structures of individuals whose physical or mental health has been most seriously impaired by a common but poorly understood condition called functional neurological disorder (FND). In their report published online in the Journal of Neurology, Neurosurgery and Psychiatry, the research team describes reductions in the size of a portion of the insula in FND patients with the most severe physical symptoms and relative volume increases in the amygdala among those most affected by mental health symptoms.

    “The brain regions implicated in this structural neuroimaging study are areas involved in the integration of emotion processing, sensory-motor and cognitive functions, which may help us understand why patients with functional neurological disorder exhibit such a mix of symptoms,” says David Perez, MD, MMSc, of the MGH Departments of Neurology and Psychiatry, lead and corresponding author of the report. “While this is a treatable condition, many patients remain symptomatic for years, and the prognosis varies from patient to patient. Advancing our understanding the pathophysiology of FND is the first step in beginning to develop better treatments.”

    One of the most common conditions bringing patients to neurologists, FND involves a constellation of neurologic symptoms — including weakness, tremors, walking difficulties, convulsions, pain and fatigue — not explained by traditional neurologic diagnoses. This condition has also been called conversion disorder, reflecting one theory that patients were converting emotional distress into physical symptoms, but Perez notes that this now appears to be an oversimplified view of a complex neuropsychiatric condition. The research team hopes that advancing the neurobiological understanding of FND will increase awareness and decrease the stigma — including skepticism about the reality of patients’ symptoms — often associated with this condition.

    Previous functional MRI studies have suggested that a group of brain structures forming part of what is called the salience network — which are involved in detecting important bodily and environmental stimuli, as well as integrating emotional, cognitive and sensory-motor experiences — showed increased activity in FND patients during a variety of behavioral and emotion-processing tasks. The current study is one of the first to examine structural relationships between components of the salience network and the physical and mental health of patients with FND.

    The researchers compared whole-brain structural MRI scans of 26 FND patients with those of 27 healthy control participants, looking for associations between the size of salience-network structures and participants’ reports of their physical health, mental health and symptoms of anxiety and depression. While there were no whole-brain structural differences between FND patients and healthy controls, patients reporting the greatest levels of physical impairment were found to have decreased volume in the left anterior insula, while those reporting the greatest mental health impairments and highest anxiety levels had increased volume within the amygdala.

    “The association among FND patients between the severity of impairments in physical functioning and reduced left anterior insular volume is intriguing, given that the anterior insula has been implicated in self- and emotional awareness,” says Perez, who is a dual trained neurologist-psychiatrist and an assistant professor of Neurology at Harvard Medical School.

    He adds, “Little attention has been given to FND to date, which is striking given its prevalence and the health care expenses driven by patients suffering with FND. I hope that advancing the neurobiological understanding of FND will help decrease the stigma often associated with this condition and increase public awareness of the unmet needs of this patient population.”


  8. Psychologists examine how to package health recommendations

    September 10, 2017 by Ashley

    From the University of Illinois College of Liberal Arts & Sciences press release:

    In the world of health care, the phrase “too much information” — or TMI — can be a serious problem. If you Google “How to prevent cancer,” for example, you will find list after list of websites claiming to have the winning strategy, with some plans presenting 20-30 steps.

    The same situation occurs if one searches for information on quitting smoking, exercising, sleep, and endless other issues. The question becomes this: When does a person receive too much health information? What’s the best way for health providers to convey information without consumers skipping over or forgetting key information?

    According to a new study from the University of Illinois, the answer lies in the goal of a specific health objective. Dolores Albarracin, professor of psychology, graduate student Jack McDonald, and colleagues at other universities studied the behavior of some 459 people to shine light on this topic that challenges health providers.

    One school of thought among health care providers is to give health information in small doses of two or three recommendations at once. Others argue that it’s best to give patients the entirety of their options, so as to not skip out on something that may prove useful. The Illinois study, published in Clinical Psychological Science, asserts that it depends on the nature of the recommendations.

    According to the researchers, presenting a large amount of information would be appropriate if the goal would be for people to remember a large amount of potentially interchangeable behaviors, but if the goal is for people to remember a complete set of important recommendations, then the best strategy should be to present relatively few recommendations.

    “The best number of health behaviors to recommend seems to depend on the goal of an intervention,” Albarracin said. “If the goal is to communicate as many recommendations as possible, then go for a long list of behaviors. But if the goal is to implement behaviors, then the best strategy may be to convey a lower number of recommended behaviors.”

    The researchers, who also included Patrick McDonald at the University of Buffalo and Colleen Hughes at Indiana University-Bloomington (both are former members of Albarracin’s research group), came to their conclusion by analyzing the results of experiments in which participants were presented with a list of brief health recommendations (ranging in number from two to 20, with each recommendation being about 33 words long). They were then asked to recall as many recommendations as they could.

    Participants were also asked open-ended questions about their intentions to follow the recommendations. Even though more recommendations meant that participants recalled a lower proportion of the total, they recalled and intended to follow more recommendations.

    “When multiple health recommendations are necessary, knowing the influence of the number of recommendations on recall and intended compliance is critical,” the researchers wrote.

    This information can prove useful in many health fields. For example, psychotherapists who want to change the behavior of their patients in specific ways could assign homework, for example, that addresses one behavior. Other health professionals might give recommendations in small bursts (perhaps via text messaging) to help maximize the proportion of recalled recommendations while minimizing the costs to a patient.


  9. Less REM sleep tied to greater risk of dementia

    September 9, 2017 by Ashley

    From the American Academy of Neurology (AAN) press release:

    People who get less rapid eye movement (REM) sleep may have a greater risk of developing dementia, according to a new study published in the August 23, 2017, online issue of Neurology®, the medical journal of the American Academy of Neurology. REM sleep is the sleep stage when dreaming occurs.

    There are five stages of sleep. Stage one is light sleep. Stage two is when the body begins to prepare for deeper sleep, including stages three and four. Stage five is REM sleep. During this dream stage, the eyes move rapidly and there is increased brain activity as well as higher body temperature, quicker pulse and faster breathing. The first REM stage occurs about an hour to an hour-and-a-half into sleep and then recurs multiple times throughout the night as the cycles repeat.

    “Sleep disturbances are common in dementia but little is known about the various stages of sleep and whether they play a role in dementia risk,” said study author Matthew P. Pase, PhD, of Swinburne University of Technology in Australia. “We set out to discover which stages of sleep may be linked to dementia and while we did not find a link with deep sleep, we did with REM sleep.”

    For the study, researchers looked at 321 people with an average age of 67 from Massachusetts who participated in The Framingham Heart Study. During that study, sleep cycles were measured for each participant. Researchers collected the sleep data and then followed participants for an average of 12 years. During that time, 32 people were diagnosed with some form of dementia and of those, 24 were determined to have Alzheimer’s disease.

    The people who developed dementia spent an average of 17 percent of their sleep time in REM sleep, compared to 20 percent for those who did not develop dementia. After adjusting for age and sex, researchers found links between both a lower percentage of REM sleep and a longer time to get to the REM sleep stage and a greater risk of dementia. In fact, for every percent reduction in REM sleep there was a 9 percent increase in the risk of dementia. The results were similar after researchers adjusted for other factors that could affect dementia risk or sleep, such as heart disease factors, depression symptoms and medication use.

    Other stages of sleep were not associated with an increased dementia risk.

    “Our findings point to REM sleep as a predictor of dementia,” said Pase. “The next step will be to determine why lower REM sleep predicts a greater risk of dementia. By clarifying the role of sleep in the onset of dementia, the hope is to eventually identify possible ways to intervene so that dementia can be delayed or even prevented.”

    Limitations of the study include a small sample size. Studies on larger groups of people need to be done to confirm findings. There was also no data available on shift work among study participants, which can cause unusual sleep patterns and possibly lead to sleep disorders.


  10. Physical activity in midlife not linked to cognitive fitness in later years

    September 8, 2017 by Ashley

    From the Johns Hopkins University Bloomberg School of Public Health press release:

    A study led by Johns Hopkins Bloomberg School of Public Health researchers that tracked activity levels of 646 adults over 30 years found that, contrary to previous research, exercise in mid-life was not linked to cognitive fitness in later years.

    The finding suggests that physical activity may not help maintain cognitive function, or help avoid or delay the onset of the debilitating conditions like dementia and Alzheimer’s. Alzheimer’s affects as many as 30 million, mostly older people throughout the world. With no known treatment or cure, researchers are trying to identify measures that might help delay Alzheimer’s onset or limit its reach.

    The study, which appears online in the Journal of Alzheimer’s Disease, did find that activity levels among study participants in the later years were associated with high cognitive function two years later. This supports earlier research findings that exercise may help to maintain cognitive fitness in the short term.

    “This study reminds us that physical activity has all sorts of benefits for people, including promoting cardiovascular health, managing optimal weight levels and maintaining bone and muscle mass,” says Alden L. Gross, assistant professor in the Bloomberg School’s Department of Epidemiology. “Unfortunately it is too early for us to say the same about exercise and Alzheimer’s, especially as a possible long-term preventive measure.”

    There is no known treatment or cure for Alzheimer’s or dementia, syndromes that involves declining memory, confusion and eventually limited ability to perform daily tasks. To date, there are no preventive measures, such as physical exercise, brain games or a diet regimen, that have been proven to help delay or altogether prevent its onset. In the US, an estimated five million adults are currently living with Alzheimer’s, according to the Centers for Disease Control and Prevention (CDC), and the CDC predicts that this number will rise to 14 million by 2050.

    The researchers undertook the study because of a growing consensus that physical activity levels helps prevent Alzheimer’s, however much of the evidence for this thinking is based on cross-sectional studies that compare responses from one group of participants with another at a given point in time or within a very short duration, typically several years. Such studies can be valuable for confirming associations, or links, but not at establishing actual causation because of what is known as reverse causation: it is possible that people who eventually develop dementia may reduce their physical activity and exercise as dementia advances. That’s where longitudinal studies, which look at the same group of participants over a long time, are more helpful.

    The researchers used data from the Johns Hopkins Precursors study, which registered students studying at Johns Hopkins School of Medicine between 1948 and 1964 and tracked them with annual questionnaires about their overall health. The researchers note that the cohort’s homogeneity — students at a selective medical school — meant that any differences in physical activity and later cognitive function could not be explained by other differences among participants.

    The median age for study participants was 46 years in 1978 and 77 years in 2008. Every several years, the questionnaire asked about exercise, physical activity and physical limitations. The researchers used responses from 1978 through 2008 from 646 participants (598 men, 48 women) to calculate so-called metabolic equivalents, which quantify physical activity levels. Participants were also asked whether they regularly exercise to a sweat.

    The team administered cognitive tests in 2008, and, using participants’ medical records, scored for dementia through 2011. The researchers identified 28, or 4.5 percent of the cohort, to have Alzheimer’s.

    No physical activity measure in mid-life was associated with late-life cognitive fitness or onset of dementia. The study confirmed findings of other cross-sectional studies, that higher levels of physical activity and exercise measured close in time to the cognitive testing were associated with better cognitive functioning. The authors also looked at whether patterns of change in physical activity levels over the life span were associated with cognitive health and found no relationships.

    The idea that exercise might play a role in preventing or limiting Alzheimer’s makes sense, the researchers say, because physical activity, at least in mouse models, has shown less accumulation of B-amyloid plaques, which are thought to play a role in dementia, including Alzheimer’s. In addition, physical activity improves blood flow to the brain, which is linked to better cognitive performance. This may explain why studies find that exercise may contribute to cognitive fitness in the short term.

    “These findings have implications for intervention work moving forward,” says Gross. “We still need to focus on causes and mechanisms of Alzheimer’s and dementia, since we don’t yet know which preventive measures may or may not work. For now, when I speak in the community about Alzheimer’s, I find that people take some relief in understanding that there wasn’t anything that anyone might have done to avoid a loved one developing Alzheimer’s. Of course, the goal for researchers is to identify factors that may help older people maintain their cognitive function into their later years. More long-term studies like the Precursors study are needed.”