Occupational class, occupational mobility and cancer incidence among middle-aged men and women: a prospective study of the French GAZEL cohort

Objective: To examine the association between occupational class, occupational mobility and cancer incidence in the 1990s. Methods: Prospective study of 14,853 men and 5493 women employed by a large French company. Incident cases (any cancer, smoking and alcohol-related, breast) were ascertained through a validated company-based cancer registry (1990-2002). Hazard ratios (HRs) by occupational class and by career-long occupational mobility were calculated adjusting for age, marital status, tobacco and alcohol consumption, weight, diet, asbestos exposure, family history of cancer, and reproductive history. Results: 359 male cancers (107 smoking and alcohol-related) and 208 female cases (120 breast cancers) were observed. Male clerks and manual workers were at high risk, particularly of smoking and alcohol-related cancers (compared to managers, age-adjusted HRs: 2.95 95% CI 1.37-6.38 and 2.18 95% CI 1.15-4.11). Adjusting for specific health behaviors and other cancer risk factors reduced this gradient (fully-adjusted HRs respectively 1.95 95% CI 0.89-4.27 and 1.54 95% CI 0.80-2.97). The risk was also associated with occupational mobility. We found no association between women's occupational class and cancer. Conclusion: The incidence of smoking and alcohol-related cancers among French men shows a strong socioeconomic gradient. Policies addressing these social disparities are needed.