Background Occupying a low socioeconomic position is associated with increased mortality risk. To disentangle this association, previous studies considered various dimensions of socioeconomic trajectories across the life course. However, they used a limited number of stages. We simultaneously examined various dimensions of the whole professional trajectory and its association with mortality.

Methods We used a large sample (337 706 men and 275 378 women) of the data obtained by linking individuals’ annual occupation (collected in 1976–2002 from a representative panel of the French salaried population in the semipublic and private sectors) with causes of death obtained from registries. All-cause and cause-specific HRs were estimated using Cox's regression models adjusted for the occupational class at the beginning of the follow-up, the current occupational class, the transition rates between occupational categories and the duration of time spent in occupational categories.

Results An increase in the time spent in the clerk class increased men and women's cardiovascular mortality risk compared with that in the upper class (HRs=1.59 (1.14 to 2.20) and 2.65 (1.14 to 6.13) for 10 years increase, respectively, for men and women). Men with a high rate of transitions had about a 1.2-fold increased risk of all-cause and external-cause mortality compared with those without transitions during their professional life. This association was also observed for women's all-cause mortality.

Conclusions Strong associations between professional trajectories and mortality from different causes of death were found. Long exposure to lower socioeconomic conditions was associated with increased mortality risk from various causes of death. The results also suggest gradual associations between transition rates and mortality.