Do Japanese workers who experience an acute myocardial infarction believe their prolonged working hours are a cause?

Cardiovascular disease related to excessive work/job stress has been a significant social concern for the Japanese public. Therefore, we conducted a cross-sectional study to (1) compare job stress levels between patients with acute myocardial infarction (AMI) patients and healthy workers, and (2) examine the types of stresses associated with patients' causal belief of AMI among patients with AMI.

Forty-seven patients admitted to the hospital with AMI and 47 healthy workers visiting a hospital for their annual physical examination were recruited in Japan. Both groups were employed full time and matched on age and gender. Job stress was assessed by the Brief Job Stress Questionnaire, which consists of four subscales: job demand, job control, support from supervisors, and support from coworkers. Causal belief was assessed by a semi-structured interview.

Compared with healthy workers (50.7+/-8.6 h), AMI patients worked significantly longer hours per week (58.3+/-15.0 h) prior to their AMI. Among AMI patients, 38% reported that job stress might have contributed to their AMI. AMI patients who reported acute stressful events at work during the month prior to AMI were 6.88 times (95% CI: 1.84, 25.75) more likely to believe that job stress/overwork caused their AMI after controlling for working hours per week and age.

Like other known cardiac risk factors, it is important for clinicians to assess patient's excessive working hours. The education and counseling of patients following AMI must take into consideration long working hours, acute stressful events at work, and the patient's perceived view of job stress.