Sleep disturbances and dementia risk: A multicenter study

Abstract Introduction Few longitudinal studies assessed whether sleep disturbances are associated with dementia risk. Methods Sleep disturbances were assessed in three population‐based studies (H70 study and Kungsholmen Project [Sweden]; Cardiovascular Risk Factors, Aging and Dementia study [Finland]). Late‐life baseline analyses (3–10 years follow‐up) used all three studies (N = 1446). Baseline ages ≈ 70 years (Cardiovascular Risk Factors, Aging and Dementia, H70), and ≈84 years (Kungsholmen Project). Midlife baseline (age ≈ 50 years) analyses used Cardiovascular Risk Factors, Aging and Dementia (21 and 32 years follow‐up) (N = 1407). Results Midlife insomnia (fully adjusted hazard ratio = 1.24, 95% confidence interval = 1.02–1.50) and late‐life terminal insomnia (fully adjusted odds ratio = 1.94, 95% confidence interval = 1.08–3.49) were associated with a higher dementia risk. Late‐life long sleep duration (>9 hours) was also associated with an increased dementia risk (adjusted odds ratio = 3.98, 95% confidence interval = 1.87–8.48). Discussion Midlife insomnia and late‐life terminal insomnia or long sleep duration were associated with a higher late‐life dementia risk.