[Night workers' exposure to harshness factors in France: Lessons learned from the 2010 SUMER Survey]

Despite the fact that French laws state that night work should be exceptional, the number of night workers has sharply increased in the past 20 years. At the same time, empirical and epidemiological studies indicate that night work has negative effects on workers' health. This is why the 2010 French pension act considered night work to be a drudgery. The aim of this study is to investigate whether night workers are more subject to other factors defined as contributing to the drudgery of work than are day workers. This article focuses on exposure to physical constraints (manual manipulation of heavy loads, awkward posture, exposure to mechanical vibrations) and aggressive physical environment (carcinogenic, mutagenic and reprotoxic chemicals [CMR], extreme temperature and noise).

Our study used the 2010 Medical Monitoring Survey of Occupational Risks [Surveillance médicale des expositions aux risques professionnels, (SUMER)] that was conducted among a sample of around 50,000 employees representative of 21.7 million French employees. We used logistic regressions to explore the potential influence of night work on the probabilities of exposure to at least one CMR, noise, thermal nuisance and physical constraints.

Even though descriptive statistics suggest that night workers are more exposed to drudgery of work than day workers, our multivariate logistic models indicate that the exposure is not always positively correlated with the number of nights worked. Moreover, the exposure differs according to gender and socio-occupational category.

Our findings suggest that night workers are more exposed to several factors defined as contributing to the drudgery of work than are day workers. Thus, they seem to face multiple disadvantages in the labor market. Preventive measures in favor of night workers should be targeted at job content as much as work organization.