Debra L. Beck and Eugene Braunwald, MD

There is evidence from prospective studies to suggest that longer working hours increase the risk of incident coronary heart disease (CHD) events. However, no studies have examined whether long working hours increases the risk of recurrent CHD events in individuals who have suffered a first myocardial infarction (MI). Trudel et al conducted a prospective study examining the effect of long working hours on the risk of recurrent CHD events.

A total of 967 patients aged 35 to 59 who returned to work after a first MI were prospectively studied. All had been treated at one of 30 hospitals across the Canadian province of Quebec.

During a mean follow-up of 5.9 years, recurrent CHD events (fatal or nonfatal MI and unstable angina) were seen in 205 patients. After adjustment for sociodemographic, lifestyle, and clinical factors, participants who worked 55 hours or more a week had a higher risk of recurrent CHD events (hazard ratio vs. 35 to 40 h/week, 1.67; p<0.05). This risk increased more in those exposed to the combination of longer work hours and more job strain (HR, 2.55; p<0.05). A linear increase after 40 hours/week was also noted.

Summary

The investigators concluded that longer working hours are associated with an increased risk of recurrent events among patients returning to work after a first MI.

Comments

In an editorial, J Li and J Siegrist wrote that the findings emphasize the need for more occupational health services integrated into cardiac rehabilitation programs to maximize secondary prevention of CHD. They also noted, however, that the findings may not be generalizable to all populations given that the sample included mostly men who were under 60 years of age and still economically active.

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