Longitudinal Assessment of Physical Activity and Cognitive Outcomes among Women at Midlife

Abstract

Importance: The increasing prevalence of cognitive decline, impairment, and dementia spurs intense interest in cognitive preservation strategies. Objective: To explore the longitudinal association between physical activity (PA) and cognitive performance among women at midlife. Design, Setting, and Participants: This cohort study is an analysis from the Study of Women's Health Across the Nation. Enrollment occurred from 1996 through 1997, and follow-up extended into 2017. Included individuals were those who had undergone cognitive measures during the first 3 cognitive test visits and had at least 1 additional cognitive measurement. Stroke prior to baseline was an exclusion, and observations were censored for subsequent stroke. Data were analyzed from June 2018 through August 2019. Exposures: Engaging in sport or exercise PA (self-reported). Main Outcomes and Measures: The Symbol Digit Modalities Test (SDMT) was used to assess cognitive processing speed. The East Boston Memory Test-Delayed (EBMT-D) was used to measure verbal episodic memory. The digit span backwards (DSB) test was used to evaluate working memory. Results: Among 1718 women with a median (range) observation time of 11.9 (0.60-13.5) years, the mean (SD) baseline age was 45.7 (2.5) years. From baseline through age 61 years, mean change in SDMT score was-0.20 annually (95% CI,-0.26 to-0.15; P