Patterns of lifestyle behaviours from mid- through later-life in relation to exceptional episodic memory performance in older women: the Nurses' Health Study

Abstract

Objectives: to model and compare patterns from mid- to late-life of body mass index (BMI), alternate Mediterranean diet (A-MeDi) and physical activity, between women with exceptional episodic memory over age 80 and cognitively average controls. Our goal was to examine if lifestyle risk factors in early adulthood may be identified which promote exceptional memory status later in life.

Methods: a case-control sample nested within the Nurses' Health Study (initiated in 1976), including 7,557 cognitively healthy participants who survived to age 80 and had a cognitive assessment at 80-87 years. We defined women with exceptional memory (n = 455) as those with a composite score of episodic memory ≥1.5 standard deviation above the mean. Then, we selected 2,275 cognitively average controls with a score within 1 standard deviation of the mean, matched by age and education. Patterns of BMI, A-MeDi and physical activity at 52-62 through age 82 years were estimated between groups using latent process mixed models.

Results: In midlife, women with exceptional episodic memory had similar BMI (mean difference [MD] = -0.07 kg/m2 [95% confidence intervals {CI}:-0.41; 0.26]) but better adherence to A-MeDi (MD = +0.25 points [0.08; 0.43]) and more physical activity (MD = +3.50 metabolic-equivalent h/week [1.97; 5.09]) than controls. However, with ageing, both groups had similar patterns; both initially gained and later lost weight, had less activity and declining diet quality (all group-by-time interactions P > 0.07).

Conclusions: our findings suggest that lifestyle factors differ primarily at earlier ages for those with exceptional versus average episodic memory, thus lifestyle may be most important in earlier life to preserve high levels of memory.

Keywords: Body mass index; Mediterranean diet; episodic memory; longitudinal study; older people; physical activity.