Atypical working hours are associated with tobacco, cannabis and alcohol use

BACKGROUND: We examined prospective associations between atypical working hours, substance use and sugar and fat consumption. METHODS: In the French population-based CONSTANCES cohort, 47,288 men and 53,324 women currently employed included between 2012 and 2017 were annually followed for tobacco and cannabis use; among them, 35,647 men and 39,767 women included between 2012 and 2016 were also followed for alcohol and sugar and fat consumption. Three indicators of atypical working hours were self-reported at baseline: working at night, weekend work and non-fixed working hours. Generalized linear models computed odds of substance use and sugar and fat consumption at follow-up according to atypical working hours at baseline while adjusting for sociodemographic factors, depression and baseline substance use if appropriate. RESULTS: Working at night was associated with increased tobacco use in women [odds ratios ranging from 1.45 to 1.48], with increased cannabis use in men [from 1.40 to 1.54] and with increased alcohol use in both men and women [from 1.12 to 1.14]. Weekend work and non-fixed working hours were associated with increased tobacco and alcohol use in both men and women [from 1.15 to 1.54 and 1.12 to 1.14, respectively]. Dose-dependent relationships were found regarding the association between working at night and tobacco use in women as well as regarding non-fixed working hours and tobacco use in both men and women (P for trends <0.001). CONCLUSIONS: The potential role of atypical working hours on substance use should be considered by public health policy makers and clinicians in information and prevention strategies. KEY MESSAGES: • Night shifts were associated with increased smoking in women with dose-dependent relationships, cannabis use in men and alcohol use in both. • Weekend work and non-fixed working hours were associated with increased alcohol and tobacco use with dose-dependent relationships in men and women.