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

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. (C) 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.