New research suggests that adults aged 60 and older who engage in sedentary behaviors for over 10 hours daily have an elevated risk of developing dementia. The study, which analyzed data from the U.K. Biobank, found that the pattern in which sedentary behavior occurs throughout the day is less significant than the total daily duration. The research underscores the need for future studies to verify causality and investigate if physical activity can mitigate dementia risk.
Individuals aged 60 and above could face a higher risk of dementia if they frequently partake in inactive activities such as sitting while watching television or driving, according to a recent study conducted by researchers from the University of Southern California and the University of Arizona.
Their study showed the risk of dementia significantly increases among adults who spend over 10 hours a day engaging in sedentary behaviors like sitting — a notable finding considering the average American is sedentary for about 9.5 hours each day.
The study, published on Tuesday, September 12 in JAMA, also revealed the way sedentary behavior is accumulated over the course of the day didn’t matter as much as the total time spent sedentary each day. Whether spent in extended periods spanning several hours or spread out intermittently throughout the day, total sedentary behavior had a similar association with dementia according to study author David Raichlen.
Research Methods and Findings
“Many of us are familiar with the common advice to break up long periods of sitting by getting up every 30 minutes or so to stand or walk around. We wanted to see if those types of patterns are associated with dementia risk. We found that once you take into account the total time spent sedentary, the length of individual sedentary periods didn’t really matter,” said Raichlen, professor of biological sciences and anthropology at the USC<span class="st">Founded in 1880, the <em>University of Southern California</em> is one of the world's leading private research universities. It is located in the heart of Los Angeles.</span>” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>USC Dornsife College of Letters, Arts and Sciences.
Researchers used data from the U.K. Biobank, a large-scale biomedical database of participants across the United Kingdom, to investigate possible links between sedentary behavior and dementia risk.
As part of a U.K. Biobank sub-study, over 100,000 adults agreed to wear accelerometers, wrist-worn devices for measuring movement, for 24 hours per day for one week. The researchers focused on a sample of approximately 50,000 adults from this sub-study over the age of 60 who did not have a diagnosis of dementia at the start of the study.
The researchers then applied a machine-learning algorithm to analyze the large dataset of accelerometer readings and classify behaviors based on different intensities of physical activity. The algorithm was able to discern between different types of activity such as sedentary behavior versus sleeping. The accelerometer data, combined with advanced computing techniques, provided researchers with an objective measure of the time spent engaging in different types of sedentary behaviors.
After an average of six years of follow-up, the researchers used inpatient hospital records and death registry data to determine dementia diagnosis. They found 414 cases positive for dementia.
Then, the team adjusted their statistical analysis for certain demographics (e.g., age, sex, education level, race/ethnicity, chronic conditions, genetics) and lifestyle characteristics (physical activity, diet, smoking and alcohol use, self-reported mental health) that could affect brain health.
Total time spent sedentary each day drives dementia risk
While high amounts of sedentary behavior were linked with an increased risk of dementia, the researchers found that there were certain amounts of sedentary behavior that were not associated with dementia.
“We were surprised to find that the risk of dementia begins to rapidly increase after 10 hours spent sedentary each day, regardless of how the sedentary time was accumulated. This suggests that it is the total time spent sedentary that drove the relationship between sedentary behavior and dementia risk, but importantly lower levels of sedentary behavior, up to around 10 hours, were not associated with increased risk,” said study author Gene Alexander, professor of psychology and psychiatry at the Evelyn F. McKnight Brain Institute at the University of Arizona and Arizona Alzheimer’sAlzheimer's disease is a disease that attacks the brain, causing a decline in mental ability that worsens over time. It is the most common form of dementia and accounts for 60 to 80 percent of dementia cases. There is no current cure for Alzheimer's disease, but there are medications that can help ease the symptoms.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Alzheimer’s Disease Research Center.
“This should provide some reassurance to those of us with office jobs that involve prolonged periods of sitting, as long we limit our total daily time spent sedentary,” said Raichlen.
The study builds on their previous research, which used self-reported health data to investigate how certain types of sedentary behavior, like sitting and watching TV, affect dementia risk more than others.
“Our latest study is part of our larger effort to understand how sedentary behavior affects brain health from multiple perspectives. In this case, wearable accelerometers provide an objective view of how much time people dedicate to sedentary behavior that complements our past analyses,” said Raichlen.
More research is needed to establish causality and whether physical activity can mitigate the risk of developing dementia, the authors said.
The study was supported by grants P30AG072980, P30AG019610, R56AG067200, R01AG064587 and R01AG072445 from the National Institutes of HealthThe National Institutes of Health (NIH) is the primary agency of the United States government responsible for biomedical and public health research. Founded in 1887, it is a part of the U.S. Department of Health and Human Services. The NIH conducts its own scientific research through its Intramural Research Program (IRP) and provides major biomedical research funding to non-NIH research facilities through its Extramural Research Program. With 27 different institutes and centers under its umbrella, the NIH covers a broad spectrum of health-related research, including specific diseases, population health, clinical research, and fundamental biological processes. Its mission is to seek fundamental knowledge about the nature and behavior of living systems and the application of that knowledge to enhance health, lengthen life, and reduce illness and disability.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>National Institutes of Health and funding from the state of Arizona, the Arizona Department of Health Services and the McKnight Brain Research Foundation. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Source: SciTechDaily
