Effort–reward imbalance and long-term benzodiazepine use: longitudinal findings from the CONSTANCES cohort

Objectives To examine the association between effort–reward imbalance and incident long-term benzodiazepine use (LTBU). Methods We included 31 077 employed participants enrolled in the French population-based CONSTANCES cohort between 2012 and 2014 who had not undergone LTBU in the 2 years before enrolment. LTBU was examined using drug reimbursement administrative databases. The effort–reward imbalance was calculated in quartiles. We computed ORs (95% CIs) for LTBU according to effort–reward imbalance over a 2-year follow-up period. We adjusted for age, gender, education, occupational grade, income, marital status, tobacco smoking, risk of alcohol use disorder, depressive symptoms and self-rated health. Results Over the 2-year follow-up, 294 (0.9%) participants experienced incident LTBU. In the univariable analysis, effort–reward imbalance was associated with subsequent LTBU with ORs of 1.79 (95% CI 1.23 to 2.62) and 2.73 (95% CI 1.89 to 3.95) for the third and fourth quartiles, respectively, compared with the first quartile. There was no interaction between effort–reward imbalance and any of the considered variables other than tobacco smoking (p=0.033). The association remained significant in both smokers and non-smokers, with higher odds for smokers (p=0.031). In the fully adjusted model, the association remained significant for the third and fourth quartiles, with ORs of 1.74 (95% CI 1.17 to 2.57) and 2.18 (95% CI 1.50 to 3.16), respectively. These associations were dose dependent (p for trend <0.001). Conclusions Effort–reward imbalance was linked with incident LTBU over a 2-year follow-up period after adjustment for sociodemographic and health-related factors. Thus, screening and prevention of the risk of LTBU should be systematised among individuals experiencing effort–reward imbalance, with special attention paid to smokers.