Cardiovascular dysfunction due to shift work

Electrocardiographic, biochemical, and physical data obtained from 237 shif t and 115 day workers without any obvious disorders were assessed to clarif y the impact of shift work on cardiovascular functions. The heart-rate corr ected QT interval (QT(c)) was significantly longer in the shift workers tha n in the day workers. However, blood pressure, working duration and biochem ical and other data were comparable between the two work groups. When multi ple regression analysis was used, shift/day work was significantly related to the QT(c) in all of the workers. The adjusted odds ratio of shift work, to the prolonged QT(c) (greater than or equal to 440 ms(1/2)) was 8.15. The prolonged QT(c) has been thought to contribute to an increased risk of car diac death. These findings, therefore, suggest that the increased risk for cardiovascular mortality in shift workers may be attributable to prolongati on of the QT(c).