Causal beliefs and behavioural self-evaluation in cardiac rehabilitation: a cross-national study in the United States and Japan

Background Patients with established cardiovascular disease (CVD) continue to face substantial residual risk of recurrent events despite optimal medical management. Beliefs about disease causation, particularly attribution to genetic versus lifestyle factors, may influence health behaviour; however, their relationship with behavioural self-evaluation remains poorly understood. This study examined (1) cross-national differences in causal beliefs between patients in the United States (US) and Japan, and (2) associations between these beliefs, exercise confidence, and behavioural self-evaluation. Methods A cross-sectional study was conducted among phase II cardiac rehabilitation patients in the US ( n = 56) and Japan ( n = 120). Causal beliefs, exercise confidence, and self-reported exercise behaviour were assessed by questionnaire. Between-group comparisons were performed using independent-samples t -tests and factorial ANOVA; associations between beliefs and behaviour were examined using binary logistic regression. Results US participants attributed their CVD more strongly to genetic factors than Japanese participants (mean ± SD: 55.33 ± 32.06% vs. 29.36 ± 30.68%; Cohen’s d = 0.83, p < 0.001), whereas Japanese participants attributed their CVD more strongly to lifestyle factors (63.55 ± 29.62% vs. 41.82 ± 30.28%; Cohen’s d = 0.73, p < 0.001). US participants demonstrated greater confidence in achieving exercise goals than Japanese participants ( p < 0.001). An exploratory interaction between disease type and genetic attribution was observed for exercise confidence ( p = 0.03). Participants with high lifestyle attribution were less likely to report their current exercise level as sufficient (behavioural self-evaluation) (OR 0.46, 95% CI 0.22–0.97, p = 0.042). Conclusions Patients’ beliefs about disease causation differ between the US and Japan and are associated with exercise confidence. The findings suggest that belief systems may represent an important psychological pathway underlying behavioural self-evaluation, with potential implications for cardiovascular secondary prevention. Importantly, beliefs may influence how patients evaluate the adequacy of their behaviour rather than behavioural engagement alone. Future longitudinal and intervention studies are warranted to determine whether interventions targeting causal beliefs and behavioural self-evaluation can improve health outcomes in cardiovascular secondary prevention.