[Shift-work and cardiovascular diseases among chemical industry workers]

In order to assess the prevalence of cardiovascular abnormalities among shift workers, who were free from such abnormalities at the time of hiring, compared to day workers and ex-shift workers, we studied the QTc interval and several cardiovascular risk factors in 61 chemical workers, including 40 shift workers, 11 day workers, and 10 ex-shift workers. We found a high prevalence rate of ischemic heart disease and conduction abnormalities among ex-shift workers (5/10, 50%). We did not observe variations in the QTc interval among the three groups. The occurrence of cardiovascular disease is a reason for moving workers to day work. Therefore, the shift workers group in our study might have been selected among subjects with a healthier lifestyle preventing side effects on their cardiovascular system.