Longitudinal Associations Between Sleep and Cognitive Function in a Cohort of Older Puerto Rican Adults: Sex and Age Interactions.

Background: Evidence on sleep duration or quality and cognitive function in diverse older adults is limited. We examined prospective associations between subjective sleep measures and cognitive function, with modifying effects of sex and age (<65 vs ≥65 years).

Methods: Data are from the longitudinal Boston Puerto Rican Health Study, Waves 2 (n = 943) and 4 (n = 444), with mean follow-up of 10.5 years (range 7.2-12.8). Subjective measures of sleep duration (short <7, ref. 7, or long ≥8 hours) and insomnia symptoms (sum of difficulty falling asleep, waking up at night, and early morning awakening), were assessed at Wave 2. Linear regression models were used to assess changes in global cognition, executive function, memory, and Mini-Mental State Examination, and tested for modifying roles of sex and age.

Results: Significant 3-way interaction (sex × age × cognition) in fully adjusted models showed greater decline in global cognitive function in older men with short (β [95% confidence interval]: -0.67 [-1.24, -0.10]) or long sleep duration (-0.92 [-1.55, -0.30]), compared to women, younger men, and older men with 7 hours of sleep. Insomnia symptoms were associated with a greater decline in memory (-0.54, [-0.85, -0.22]) among older men, compared to women and younger men.

Conclusion: Sleep duration showed a U-shaped association with cognitive decline, and insomnia symptoms were associated with memory decline in fully adjusted models. Older men, versus women and younger men, were at relatively greater risk for cognitive decline associated with sleep factors. These findings are important for personalizing sleep interventions to support cognitive health.