Can Older Adults Walk Their Way Out of Dementia?

Megan Brooks

August 05, 2021

DENVER ― Low to moderate levels of physical activity in later life significantly mitigate the increased risk for age-related dementia, new research suggests.

New data from the English Longitudinal Study of Aging (ELSA) show that adults aged 80 years and older who engaged in moderate to high levels of physical activity were at lower risk for all-cause dementia than inactive adults who were in their 50s and 60s.

"These findings have important public health implications, because we know that age is the strongest risk factor for all-cause dementia and sedentary behaviors are increasing, both in younger people and older people who may have difficulties in achieving the recommended levels of physical activity," said lead investigator Natan Feter, PhD, Federal University of Pelotas, in Pelotas, Brazil.

"Even moderate-intensity physical activity once per week can reduce the risk of dementia. We had previously shown this effect on people with mild cognitive impairment. Here, we showed this effect for the overall older population," Feter told Medscape Medical News.

The findings were presented here at the Alzheimer's Association International Conference (AAIC) 2021.

Attenuating, Eliminating Risk

As part of the ELSA study, adults aged 50 years and older were followed between 2002 and 2019. On the basis of responses to a validated questionnaire, participants were classified as being inactive or engaging in low or moderate to high levels of physical activity.

Feter reported data for 8270 ELSA participants (mean age, 64 years; 56% women).

Over 17 years of follow-up, about 8% of these participants developed dementia. The risk for dementia increased by 7.8% for each year increase in age.

However, risk for all-cause dementia was reduced for those who engaged in low (odds ratio [OR], 0.30; 95% CI, 0.25 – 0.36) and moderate to high (OR, 0.13; 95% CI, 0.10 – 0.16) levels of physical activity compared with their inactive peers.

Feter said it is particularly noteworthy that adults aged 80 and older who engaged in moderate to high levels of physical activity were at lower risk for dementia than inactive adults aged 50 to 69 years.

"In our opinion, this is the study's main finding," he said.

Although aging is the strongest risk factor for dementia, "we showed that moderate-intensity physical activity once per week can attenuate, or even eliminate, the risk of dementia associated with aging," Feter noted. "In fact, older adults engaging in regular physical activity have a lower risk of dementia than adults aged up to 30 years younger."

However, he noted several study limitations, including the way that physical activity and dementia were assessed and that reverse causality and residual confounding "might not be ruled out from our findings."

Good for the Heart, Good for the Brain

Weighing in on the research for Medscape Medical News, Claire Sexton, DPhil, director of scientific programs and outreach for the Alzheimer's Association, said the results are "very consistent with other findings" that have shown a link between physical activity and reduced risk for dementia.

"Exercise has established beneficial effects on the cardiovascular system, and what's good for the heart is good for the head," said Sexton, who was not involved with the research.

"We do need further studies, including interventional studies, looking at not only exercise but combining exercise with other factors associated with reduced risk for dementia, such as cognitive activities and diet," she added.

Those studies, such as the US Pointer study, have already started. "And we kind of wait with bated breath to see those results being reported out in the coming years," said Sexton.

The study had no commercial funding. Feter and Sexton have reported no relevant financial relationships.

Alzheimer's Association International Conference (AAIC) 2021: Session 1-HO-10. Presented July 26, 2021.

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