Sleep characteristics and risk of dementia and Alzheimer's disease: The Atherosclerosis Risk in Communities Study

Abstract Introduction This study tested the hypotheses that late‐midlife obstructive sleep apnea (OSA) and short and long sleep duration are associated with dementia over 15 years of follow‐up. Methods A total of 1667 Atherosclerosis Risk in Communities Study participants underwent in‐home polysomnography (1996–1998) and were followed for dementia. Dementia was defined by (1) hospitalization diagnosis codes (1996–2012) and (2) a comprehensive neurocognitive examination (2011–2013) with adjudication. Results OSA and sleep duration were not associated with risk of incident dementia. When using adjudicated outcomes, severe OSA (≥30 vs. <5 apnea‐hypopnea events/hour) was associated with higher risk of all‐cause dementia (risk ratio [95% confidence interval], 2.35 [1.06–5.18]) and Alzheimer's disease dementia (1.66 [1.03–2.68]); associations were attenuated with cardiovascular risk factor adjustment. Sleeping <7 versus 8 to ≤9 hours was associated with higher risk of all‐cause dementia (2.00 [1.03–3.86]). Discussion When adjudicated outcome definitions were used, late‐midlife OSA and short sleep duration were associated with all‐cause and Alzheimer's disease dementia in later life.