title: The role of familial factors in the associations between sickness absence and disability pension or mortality.
abstract: BACKGROUND
  Little is known about the factors influencing the future situation of individuals on sickness absence (SA) or disability pension (DP). The aim was to investigate whether being sickness absent is associated with future DP and premature death, and whether such associations can be explained by familial factors.
  
  
  METHODS
  A sample of 45 734 Swedish twins was followed for 13 years. Cox proportional hazard models were applied to analyse the associations between having a new SA spell/being granted DP in 1995 and DP/mortality during follow-up 1996-2008. The familial confounding was tested by studying twins that were different in their exposure to SA and DP, respectively, during 1995.
  
  
  RESULTS
  SA strongly predicted DP during a follow-up of 13 years, in both women [hazard ratios (HR) 3.03, 95% confidence intervals (CI) 2.82-3.25] and men (HR 3.83, 95% CI 3.50-4.18). A minor part of the associations seemed to be explained by familial factors. Both SA and DP increased risk for mortality. For SA, HR was 1.46 (1.27-1.69) for women and 1.31 (1.14-1.51) for men. For DP, HR was 1.38 (0.92-2.05) for women and 1.73 (1.24-2.42) for men; results suggested a small influence of familial factors.
  
  
  CONCLUSIONS
  SA was found to be a long-term risk factor for DP and premature death, in both women and men. Familial factors played no or a minor role for these associations. Being granted DP in 1995 also increased risk for premature death, with a slight indication of familial influences in both sexes.
authors.affiliation: 1 Division of Insurance Medicine, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Jurgita
authors.initials: J
authors.lastname: Narusyte
authors.forename: Annina
authors.initials: A
authors.lastname: Ropponen
authors.forename: Kristina
authors.initials: K
authors.lastname: Alexanderson
authors.forename: Pia
authors.initials: P
authors.lastname: Svedberg
mesh_terms: D000368:Aged; D006233:Persons with Disabilities / Q000706:statistics & numerical data*; D004200:Diseases in Twins / Q000453:epidemiology / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D061213:Mortality, Premature; D010415:Pensions / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D012307:Risk Factors; D012737:Sex Factors; D018582:Sick Leave / Q000706:statistics & numerical data*; D013548:Sweden / Q000453:epidemiology; D014427:Twins / Q000706:statistics & numerical data*; D014429:Twins, Dizygotic / Q000706:statistics & numerical data; D014430:Twins, Monozygotic / Q000706:statistics & numerical data