(P17-044-25) Association of Long-Term Physical Activity Levels With Dementia Risk and Cognitive Function in US Adults

Objectives: To prospectively examine the associations between long-term physical activity and dementia and cognitive function.

Methods: Discretionary physical activity was assessed every 2 to 4 years in the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS) via self-administered questionnaires. Dementia was ascertained from 62,890 NHS participants and 42,159 HPFS participants during up to 29 years of follow-up. Objective cognitive function was assessed using Telephone Interview for Cognitive Status among 12,837 NHS participants. Subjective cognitive decline (SCD) was self-reported by 19,744 NHS participants and 12,906 HPFS participants. An 8-year lag analysis was applied to minimize reverse causation.

Results: Participants in the highest quartile of total physical activity had a 17% lower dementia risk [Hazard Ratio (HR) = 0.83; 95% Confidence Interval (CI): 0.78-0.88; P _linearity < 0.001] and a 28% lower SCD risk [Relative Risk (RR) = 0.72; 95% CI: 0.64–0.80; P _linearity < 0.001], compared to the lowest quartile. Compared to those in the lowest tertile of walking time, participants in the highest tertile had a 6% lower risk of dementia (HR = 0.94; 95% CI: 0.90-0.99; P _linearity = 0.03) and a 19% lower risk of SCD (RR = 0.81; 95% CI: 0.74–0.90; P _linearity < 0.001). Across tertiles, a higher level of vigorous aerobic exercise was associated with 11% lower dementia risk (HR = 0.89; 95% CI: 0.84-0.93; P _linearity < 0.001) and 18% lower SCD risk (RR = 0.82; 95% CI: 0.74–0.90; P _linearity < 0.001). Each 1-hour/day increment in total physical activity was associated with 0.73 fewer years of cognitive aging in global cognition [Mean Difference (MD) = -0.73; 95% CI: -1.21– -0.24; P _linearity=0.003] and 0.80 fewer years in verbal memory (MD = -0.80; 95% CI: -1.31– -0.28; P _linearity=0.003). Participants with the highest tertile of vigorous aerobic exercise showed 1.02 fewer years of cognitive aging in global cognition (MD = -1.02; 95% CI: -1.50– -0.54; P _linearity < 0.001) and 1.08 fewer years in verbal memory (MD = -1.08; 95% CI: -1.60– -0.57; P _linearity < 0.001), compared to those in the lowest tertile. In men only, weightlifting was independently associated with a 32% lower SCD risk (RR = 0.68; 95% CI: 0.54–0.86; P _linearity=0.002).

Conclusions: Physical activity was associated with a lower dementia risk and better cognition.

Funding Sources: NIH