Objectives: Long working hours have been associated with cardiovascular disease (CVD) mortality. However, results are inconsistent and large cohort studies are needed to confirm these findings.
Methods: We conducted a census-based cohort study including 11,903,540 Italian workers aged 20-64 years, registered in the 2011 census, with a 5-year follow-up (2012-2016). We estimated cause-specific hazard ratios (cHRs) through Cox regression models to quantify the association between long working hours and CVD mortality.
Results: Over 5 years of follow-up, 17,206 individuals died from CVD (15,262 men and 1944 women). Men working 55 or more hours per week had a cHR of 0.95 (95% confidence interval, CI 0.89-1.02) for all CVDs, while women showed a cHR of 1.19 (95% CI 0.95-1.49). Professional women working more than 55 h per week had a cHR of 1.98 (95% CI 0.87-4.52).
Conclusions: This study does not support an association between long working hours and CVD mortality among active Italian men, while it suggests a possible excess risk among women, although based on limited number of events.
Keywords: Cardiovascular diseases; Long working hours; Mortality; Occupation; Overtime work; Workers.