Occupational and behavioural factors in the explanation of social inequalities in premature and total mortality: a 12.5-year follow-up in the Lorhandicap study

Abstract

The respective contribution of occupational and behavioural factors to social disparities in all-cause mortality has been studied very seldom. The objective of this study was to evaluate the role of occupational and behavioural factors in explaining social inequalities in premature and total mortality in the French working population. The study population consisted of a sample of 2,189 and 1,929 French working men and women, who responded to a self-administered questionnaire in mid-1996, and were followed up until the end of 2008. Mortality was derived from register-based information and linked to the baseline data. Socioeconomic status was measured using occupation. Occupational factors included biomechanical and physical exposures, temporary contract, psychological demands, and social support, and behavioural factors, smoking, alcohol abuse, and body mass index. Significant social differences were observed for premature and total mortality. Occupational factors reduced the hazard ratios of mortality for manual workers compared to managers/professionals by 72 and 41%, from 1.88 (95% CI: 1.17-3.01) to 1.25 (95% CI: 0.74-2.12) for premature mortality, and from 1.71 (95% CI: 1.18-2.47) to 1.42 (95% CI: 0.95-2.13) for total mortality. The biggest contributions were found for biomechanical and physical exposures, and job insecurity. The role of behavioural factors was very low. Occupational factors played a substantial role in explaining social disparities in mortality, especially for premature mortality and men. Improving working conditions amongst the lowest social groups may help to reduce social inequalities in mortality.