Working conditions in the explanation of occupational inequalities in sickness absence in the French SUMER study.

Background: Explanations of social inequalities in sickness absence are lacking in the literature. Our objectives were to evaluate the contribution of various occupational exposures in explaining these inequalities in a national representative sample of employees.
Methods: The study was based on the cross-sectional sample of the SUMER 2010 survey that included 46 962 employees, 26 883 men and 20 079 women. Both sickness absence spells and days within the last 12 months, as health indicators, were studied. Occupation was used as a marker of social position. The study included both psychosocial work factors (variables related to the classical job strain model, psychological demands, decision latitude, social support and understudied variables related to reward, job insecurity, job promotion, esteem, working time/hours and workplace violence) and occupational exposures of chemical, biological, physical and biomechanical nature. Weighted age-adjusted Poisson and negative binomial regression analyses were performed.
Results: Strong occupational differences were found for sickness absence spells and days and for exposure to most work factors. Psychosocial work factors contributed to explain occupational differences in sickness absence spells, and the contributing factors were: decision latitude, social support, reward, shift work and workplace violence. Physical exposure, particularly noise, and biomechanical exposure were also found to be contributing factors. Almost no work factor was found to contribute to occupational differences in sickness absence days.
Conclusion: Preventive measures at the workplace oriented towards low-skilled occupational groups and both psychosocial work factors and other occupational exposures may be beneficial to reduce sickness absence spells and occupational differences in this outcome.