title: A change in sleep pattern may predict Alzheimer disease.
abstract: OBJECTIVE
  Sleep problems may adversely affect neuronal health. We examined a subjective report of change (reduced duration and/or depth) in sleep pattern in relation to subsequent risk of incident all-cause dementia and Alzheimer disease (AD) over 9 years.
  
  
  METHODS
  This longitudinal study used data from a population-based sample of 214 Swedish adults aged 75 and over who were dementia-free both at baseline and at first follow-up (3 years later). The sample was 80% female and, on average, 83.4 years of age at baseline. All participants underwent a thorough clinical examination to ascertain all-cause dementia and AD.
  
  
  RESULTS
  Forty percent of participants reported a change in sleep duration at baseline. Between the 6th and 9th year after baseline, 28.5% were diagnosed with all-cause dementia, 22.0% of whom had AD. Reduced sleep was associated with a 75% increased all-cause dementia risk (hazard ratio: 1.75; 95% confidence interval: 1.04-2.93; Wald = 4.55, df = 1, p = 0.035) and double the risk of AD (hazard ratio: 2.01; 95% confidence interval: 1.12-3.61; Wald = 5.47, df = 1, p = 0.019) after adjusting for age, gender, and education. The results remained after adjusting for lifestyle and vascular factors but not after adjusting for depressive symptoms. No evidence supported a moderating effect of the use of sleeping pills, and the sleep-dementia relationship remained after controlling for the presence of the apolipoprotein E ε4 allele.
  
  
  CONCLUSIONS
  Self-reported sleep problems may increase the risk for dementia, and depressive symptoms may explain this relationship. Future research should determine whether treatment, in particular, behavioral or nonpharmacologic treatment, may represent one avenue toward reduction of dementia risk in late life.
authors: Department of Psychology, Brandeis University, Waltham, MA.
authors: Elizabeth A
authors: EA
authors: Hahn
authors: Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University, Stockholm, Sweden. Electronic address: huixin.wang@ki.se.
authors: Hui-Xin
authors: HX
authors: Wang
authors: School of Aging Studies, University of South Florida, Tampa, FL; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.
authors: Ross
authors: R
authors: Andel
authors: Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University, Stockholm, Sweden.
authors: Laura
authors: L
authors: Fratiglioni
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000209:etiology*; D003863:Depression / Q000150:complications / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016016:Proportional Hazards Models; D012307:Risk Factors; D012893:Sleep Wake Disorders / Q000150:complications* / Q000453:epidemiology; D013548:Sweden / Q000453:epidemiology
keywords: Sleep disturbances; dementia; longitudinal; older adults