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Older adults who spend too much time sitting could face an increased risk for dementia, study says

Older adults who spend a lot of time sitting could be at a heightened risk for dementia, according to a study published this month in the JAMA medical journal.SAFIN HAMID/AFP via Getty Images

There’s really no way to couch this.

Older adults who spend a lot of time sitting could be at a heightened risk for dementia, according to a study published this month in the JAMA medical journal.

“Among older adults, more time spent in sedentary behaviors was significantly associated with higher incidence of all-cause dementia,” said the study, which was released Sept. 12 and authored by researchers at the University of Southern California and University of Arizona. “Future research is needed to determine whether the association between sedentary behavior and risk of dementia is causal.”

The study culled data from nearly 50,000 adults in the United Kingdom 60 and older who weren’t diagnosed with dementia when the research began in 2013. The average age of participants was 67, and 54 percent were female.

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David Raichlen, a USC professor of biological sciences and anthropology and an author of the study, recently tweeted that dementia risks “are not significant up until around 10 hrs/day of sedentary time. Risks of dementia rise substantially at higher amounts of sedentary time.”

Participants wore a device called a wrist accelerometer to track their levels of “sedentary behavior” and follow-up analysis was conducted “for a mean of 6.72 years,” the study said.

During that period, 414 subjects were diagnosed with “all-cause dementia,” the researchers found.

“There was a significant nonlinear association between time spent in sedentary behavior and incident dementia,” the study said.

“Of course, this is an observational study and we can’t determine whether these links are causal,” Raichlen posted on X, formerly known as Twitter. “But with more and more evidence that sedentary behaviors are linked with adverse health outcomes, moving more and sitting less is a safe bet for improving health outcomes.”

More than 55 million people worldwide suffer from dementia, according to the World Health Organization, which lists a number of factors that can increase the risk, including high blood pressure, diabetes, obesity, smoking, hard drinking, physical inactivity, social isolation, and depression.

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Dr. Andrew E. Budson, chief of cognitive and behavioral neurology at the VA Boston Healthcare System and the author of “Seven Steps to Managing Your Aging Memory,” said by email that the study begins to explain why people living in so-called “blue zones,” where humans have lived longer, tend to have reduced rates of dementia as they age.

“Rather than exercising vigorously for a short period of time, individuals who live in these blue zones are generally active throughout the day,” wrote Budson, a neurology professor at the Boston University School of Medicine.

The study suggests that “all of us can do more to reduce our chances of developing dementia in later life, particularly when we are in our 60s, 70s, and beyond,” he said.

It’s “the total time being sedentary that matters — so walking around for 5 minutes each hour is not sufficient if we still end up sitting at work, lunch, dinner, and in front of the TV for more than 9 hours each day,” he said. “The way that I would prefer to think about it is that if there are roughly 16 hours each day when we are awake, we want to make sure that we are moving for at least 7 of these hours each day.”


Travis Andersen can be reached at travis.andersen@globe.com.