The purpose of the study was to examine the association between working hours, job strain, and duration of prehospital delay in seeking care by employed patients with acute coronary syndrome (ACS) in the United States and Japan.

In this cross-sectional study, a total of 234 consecutive patients (Americans, n = 148; mean age, 50.7 [SD ± 7.1] years and 73.6% male, and Japanese, n = 86; mean age, 56.3 [SD ± 11.0] years and 93.0% male) admitted with ACS who worked more than 20 h/wk were recruited. A structured interview was conducted while patients were hospitalized to assess prehospital delay time, ambulance use, number of working hours per week, and job strain.

In the US sample, the median delay time was 4.4 hours, whereas in the Japanese sample, the median delay time was 8.3 hours. Average working hours per week in the US and Japanese samples were 49.7 (SD ± 13.2) hours and 55.1 (SD ± 19.5) hours, respectively. In multivariate analysis, the interaction between working hours and nationality on log-transformed delay time was significant (P = .001) after controlling for potential confounding factors. Among the Japanese sample, for every 1-hour increase in working hours per week, prehospital delay increased by approximately 4% (95% confidence interval [CI]; 1.0%-7% [P = .003]). However, among the US sample, no association was found (−2.0%; 95% CI, −4.0% to 0%; P = .08).

These findings support the need for worksite educational programs, particularly in Japan, that encourage a rapid response to acute cardiac symptoms.