Objectives: Our aims were to study to what extent chronically ill workers (CIWs) take more sick leave than non-chronically ill workers (NCIWs) and to explore which health-related and work-related aspects are associated with the sick leave patterns of the two groups.
Methods: A questionnaire on work, health and sick leave was sent to all employees of a university in The Netherlands (response: 49.1%). Analyses were conducted for 444 CIWs and 1,347 NCIWs. Odds ratios (ORs) were calculated to quantify the contribution of being chronically ill to sick leave in general, frequent sick leave, prolonged sick leave, and present sick leave. The contributions of health-related and work-related aspects to sick leave were investigated by multiple logistic regression analyses for both CIWs and NCIWs separately.
Results: CIWs showed significantly increased ORs for general, frequent, prolonged and present sick leave when compared with NCIWs. Fatigue, emotional exhaustion and perceived health complaints showed stronger associations with sick leave for both CIWs and NCIWs than various work-related aspects. Workers of 46 years of age and older showed less sick leave than workers under the age of 36. Male respondents and scientific personnel showed less frequent sick leave than the other respondents, and so did respondents working more than 40 h a week, compared with part-timers. The final regression models explained 8%-16% of the variance in sick leave.
Conclusions: CIWs take two to three times more and longer sick leave than NCIWs. Health-related aspects are more strongly associated with sick leave than work-related aspects for both CIWs and NCIWs. Sick leave patterns were, nevertheless, only partly explained by health-related and work-related aspects. In any case, future studies of sick leave should certainly take the presence of chronic disease into account as an important determinant of sick leave.