Type A behaviour and risk of coronary heart disease: The JPHC Study

Background Although numerous studies of type A behaviour and risk of coronary heart disease (CHD) have been reported in the west (with mixed findings), few studies have been carried out in Asian populations. Methods We examined prospectively the association between type A-behaviour and risk of CHD incidence within a cohort of 86 361 Japanese men and women aged 4069 years. A total of 669 cases of newly diagnosed CHD occurred between the baseline questionnaire (199094) and the end of follow-up in January 2004. Results We found no overall evidence of an association between type A and CHD incidence. The multivariate hazard ratio (HR) and 95 confidence intervals for CHD incidence in the highest vs lowest level of type A was 1.19 (0.941.51) overall. Contrary to expectation, Japanese men with lower levels of type A behaviour (lower levels of impatience, aggressiveness and competitiveness) appeared to be at significantly increased risk of CHD incidence (HR 1.32; 95 CI 1.021.72). In contrast to men, there was insignificant but a tendency for reduced risk of CHD incidence (HR 0.79, 95 CI 0.461.34) for women with lower levels of type A behaviour. Conclusions Type A behaviour does not predict CHD incidence in the Japanese population. Among males, type B behavioural patterns appear to confer increased CHD risk. Our findings suggest that the cardio-toxic effect of type A behaviour is gender-specific and culturally contingent.