Midlife physical activity and late-life subjective cognitive complaints in women.

BACKGROUND AND OBJECTIVES: Alzheimer's disease affects mostly women over 65, who make up nearly two-thirds of cases. Subjective cognitive complaints (SCC) can precede Alzheimer's disease by years. While physical activity supports healthy aging, the long-term impact of midlife physical activity (PA) on late-life SCCs in women is limited. RESEARCH DESIGN AND METHODS: Using data from 4,397 participants (mean age=46.2 years at baseline; 78.7 years at SCC assessment) in the New York University Women's Health Study (NYUWHS), a prospective cohort of 14,274 women enrolled in 1985-1991, we examined the association between midlife PA and SCC reported nearly 30 years later. PA was assessed at baseline using self-reported weekly hours of mild, moderate, and vigorous activity, converted to metabolic equivalent hours per week (MET-hours/week). Odds ratios and 95% CIs were estimated using unconditional logistic regression, adjusting for demographics and midlife and late-life health conditions. Multiple imputation and inverse probability weighting addressed missing data and potential selection bias. RESULTS: Women in the highest tertile of total midlife PA had 20% lower odds of reporting ≥2 SCCs compared with those in the lowest tertile (OR = 0.80; 95% CI = 0.68-0.95). The inverse association was stronger among never smokers (OR = 0.68; p for interaction=0.029). The inverse association was consistent for moderate and vigorous, but not mild PA. Findings were consistent across sensitivity analyses using alternative SCC definitions, exclusion criteria, and inverse probably weights. DISCUSSION AND IMPLICATIONS: Higher level of midlife PA was associated with fewer late-life SCCs, suggesting that midlife PA may be an important behavioral correlate of later-life cognitive health in women.