Leading a healthy lifestyle, including regular exercise, eating fruits and vegetables, and minimal alcohol consumption, is associated with better cognitive function in older adults, new research showed.
The study, which combined longitudinal and cohort data with postmortem brain pathology reports, found that the association held even in those with Alzheimer’s disease (AD) pathology, suggesting that lifestyle factors may provide cognitive reserve and improve cognitive abilities in older age.
“While we must use caution in interpreting our findings, in part due to its cross-sectional design, these results support the role of lifestyle in providing cognitive reserve to maintain cognitive function in older adults despite the accumulation of common dementia-related brain pathologies,” Klodian Dhana, MD, of the Rush University Medical Center in Chicago, Illinois, and colleagues wrote.
The study was published online on February 5 in JAMA Neurology.
Better Cognition
The study included 586 participants (71% female) who were followed from 1997 until 2022 as part of the Rush Memory and Aging Project longitudinal cohort study.
Investigators collected information on lifestyle and demographic factors at regular intervals, as well as information on diet, alcohol intake, and time spent participating in moderate or vigorous physical activity such as gardening, walking, calisthenics, biking, or swimming. Participants also received annual cognitive tests.
In later years, participants answered questions about whether they played card games or checkers, read, visited a museum, or did other cognitively stimulating activities.
Postmortem exams allowed the researchers to assess brain pathology (mean age at death, 91 years).
Participants were categorized as living a healthy lifestyle if they scored well in five categories: They exercised moderately or vigorously for 150 minutes per week, did not smoke, consumed one to two drinks per week, regularly played card games or did puzzles, and followed the Mediterranean-DASH Diet Intervention for Neurodegenerative Delay diet.
For every one-point increase in the healthy lifestyle score, there were 0.120 fewer units of beta-amyloid load in the brain and a 0.22 standardized unit higher score in cognitive performance (P < .001).
After adjusting for the beta-amyloid load, phosphorated tau tangle, or other dementia-related brain pathologies, the healthy lifestyle score remained independently associated with cognition (P < .001).
More than 88% of a person’s global cognition score was a “direct association of lifestyle,” investigators noted, leaving slightly less than 12% affected by the presence of beta-amyloid.
“The mechanistic link between lifestyle and cognition could be attributed in part to the antioxidant and anti-inflammatory capacities of each lifestyle factor (eg, nutrition and physical activity) and cognitive reserve (eg, cognitive activities) that contribute to less inflammation and oxidative stress,” the authors wrote.
Further studies are necessary, they added, especially research investigating the association of lifestyle factors with markers for inflammation to understand the mechanisms of how lifestyle is associated with better cognitive scores in old age.
Study limitations include the reliance on self-reported data because cognitive impairment could interfere with inaccurate reporting. In addition, the authors noted that cognitive abilities may affect adherence to lifestyle factors.
‘Important Evidence’
In an accompanying editorial, Yue Leng, MD, and Kristine Yaffe, MD, of the University of San Francisco in San Francisco, California, noted that the new study adds “important evidence” to the debate over modifiable risk factors and reduction of AD risk.
“These interesting results add strength to the concept that health and lifestyle factors are important strategies for prevention and suggest that several mechanisms may be at work,” they wrote, adding that the study is “one of the first to harness brain pathology to investigate these mechanisms and is a crucial step forward in addressing these important questions.”
Still, critical questions remain regarding the mechanistic pathways linking modifiable risk factors and cognitive aging, Leng and Yaffe wrote.
“There is an urgent need for more well-designed randomized controlled trials to pave the way for dementia risk reduction in the era of precision medicine,” they wrote. “These strategies should be offered in conjunction with AD medications, similar to the approach in cardiovascular disease prevention and treatment in which medications along with lifestyle strategies are the standard of care.”
The study was funded by the National Institute on Aging. Dhana reported grants paid to his institution from the Alzheimer’s Association. No other disclosures were reported.
