title: Depressive symptoms, life satisfaction and prevalence of sleep disturbances in the general population of Germany: results from the Heinz Nixdorf Recall study.
abstract: OBJECTIVE
  It appears that not only depression, but also low life satisfaction (LS), is related to sleep disorder in the general population. We evaluate whether the prevalence of sleep disorder attributable to depressed mood is greater among participants with low LS.
  
  
  METHODS
  Analysis of cross-sectional data from 3880 cohort members from the German Heinz Nixdorf Recall study (2006-2008) aged 51-81 years. Standard mood (Center for Epidemiological Studies Depression scale (CES-D) for Depressive symptoms and a single-item life satisfaction measure) and sleep quality (Pittsburgh Sleep Quality Index, PSQI) measures were conducted as part of the survey. Multiple imputation was used to deal with missing data in outcome, exposures or covariates. Relative excess risk for interaction (RERI) and its 95% CIs were estimated using adjusted prevalence ORs. Owing to the study size, the precision of the measures of additive interaction is relatively low.
  
  
  RESULTS
  We observed an association between depressed mood (5-units increase in CES-D score) (POR=1.7 (95% CI 1.6 to 1.8)) and sleep disorder, and between low LS (not very satisfied vs very satisfied) (POR=1.5 (1.1 to 2.2)) and sleep disorder. Also, we observed a synergistic effect between lower level of LS (not very satisfied) and depressed mood (score ≥ 16) on prevalence of sleep disorders (RERI=3.7 (-0.2 to 7.1)). Furthermore, these findings were corroborated in sensitivity analysis carried out with the complete case data set and in sex-specific analyses (RERI=5.5 (-0.4 to 11.3), and RERI=2.4 (-2.5 to 7.4) for men and women, respectively).
  
  
  CONCLUSIONS
  Both depressed mood and LS are notably associated with sleep quality, and these relationships are best captured by considering their joint effects. Depression and LS need to be taken into consideration when analysing sleep quality.
authors.affiliation: Medical Faculty, Martin-Luther-University, Institute of Medical Epidemiology, Biostatistics and Informatics, Halle, Germany.
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Lacruz
authors.affiliation: Medical Faculty, Martin-Luther-University, Institute of Medical Epidemiology, Biostatistics and Informatics, Halle, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Schmidt-Pokrzywniak
authors.affiliation: Medical Faculty, Heinrich-Heine-University Düsseldorf, Institute for Medical Sociology, University Düsseldorf, Duesseldorf, Germany.
authors.forename: Nico
authors.initials: N
authors.lastname: Dragano
authors.affiliation: Institute of Medical Informatics, Biometry and Epidemiology, University Duisburg-Essen, Essen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Moebus
authors.affiliation: Medical Faculty, Martin-Luther-University, Institute of Medical Epidemiology, Biostatistics and Informatics, Halle, Germany.
authors.forename: Susanne Eva
authors.initials: SE
authors.lastname: Deutrich
authors.affiliation: Medical Clinic II, Moers, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Möhlenkamp
authors.affiliation: Cardioangiological Center Bethanien, Frankfurt/Main, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Schmermund
authors.affiliation: Department of Cardiology, West-German Heart Center Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Hagen
authors.initials: H
authors.lastname: Kaelsch
authors.affiliation: Department of Cardiology, West-German Heart Center Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Raimund
authors.initials: R
authors.lastname: Erbel
authors.affiliation: Institute of Medical Informatics, Biometry and Epidemiology, University Duisburg-Essen, Essen, Germany Department of Epidemiology, School of Public Health, Boston University, Boston, USA.
authors.forename: Andreas
authors.initials: A
authors.lastname: Stang
mesh_terms: D000339:Affect; D000368:Aged; D003430:Cross-Sectional Studies; D003863:Depression / Q000150:complications*; D003866:Depressive Disorder / Q000150:complications; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D010549:Personal Satisfaction; D015995:Prevalence; D012307:Risk Factors; D012890:Sleep; D012893:Sleep Wake Disorders / Q000453:epidemiology / Q000209:etiology* / Q000523:psychology; D011795:Surveys and Questionnaires
keywords: depressed mood; interaction; life satisfaction; sleep quality