title: Low medically certified sickness absence among employees with poor health status predicts future health improvement: the Whitehall II study.
abstract: BACKGROUND
  High sickness absence is associated with poor health status, but it is not known whether low levels of sickness absence among people with poor health predict future health improvement.
  
  
  OBJECTIVE
  To examine the association between medically certified sickness absence and subsequent change in health among initially unhealthy employees.
  
  
  METHODS
  5210 employees (3762 men, 1448 women) whose self-rated health status remained stable (either good or poor) between data phases 1 and 2 were divided into three groups according to their rate of medically certified absences during this period (0 vs >0-5 vs >5 absence spells longer than 7 days per 10 person-years). Subsequent change in health status was determined by self-rated health at follow-up (phase 3).
  
  
  RESULTS
  After adjustment for age and sex, there was a strong contemporaneous association between lower sickness absence and better health status. Among participants reporting poor health, low absence was associated with subsequent improvement in health status (odds ratio 2.66, 95% CI 1.78 to 4.02 for no absence vs >5 certified spells per 10 years). This association was only partially explained by known existing morbidity, socioeconomic position and risk factors.
  
  
  CONCLUSIONS
  Low levels of medically certified sickness absence seem to be associated with positive change in health status among employees in poor health. Further research is needed to examine whether lower sickness absence also marks a more favourable prognosis for specific diseases.
authors.affiliation: Department of Epidemiology and Public Health, University College London Medical School, 1-19 Torrington Place, London WC1E 6BT, UK. m.kivimaki@ucl.ac.uk
authors.forename: M
authors.initials: M
authors.lastname: Kivimäki
authors.forename: J E
authors.initials: JE
authors.lastname: Ferrie
authors.forename: M J
authors.initials: MJ
authors.lastname: Shipley
authors.forename: J
authors.initials: J
authors.lastname: Vahtera
authors.forename: A
authors.initials: A
authors.lastname: Singh-Manoux
authors.forename: M G
authors.initials: MG
authors.lastname: Marmot
authors.forename: J
authors.initials: J
authors.lastname: Head
mesh_terms: D000328:Adult; D005260:Female; D005544:Forecasting; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008004:Licensure; D008131:London; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology*; D011446:Prospective Studies; D018582:Sick Leave; D014940:Work Schedule Tolerance