Background: Most data about psychological factors relating to acute myocardial infarction (AMI) were obtained from studies carried out in western countries. Results from small descriptive cross-sectional studies in China were inconclusive. The aim of this study was to explore possible associations between psychological risk factors and AMI among the Chinese population with a large-scale case-control study.
Methods: This study was part of the INTER-HEART China study, itself part of the large international INTER-HEART study of cardiovascular risk factors. In this case-control study, 2909 cases and 2947 controls were recruited from 17 cities. Psychological stress, negative life events, depression and controllability of life circumstances were assessed.
Results: Cases reported more psychological stress at home or work and odds ratios (ORs) were 3.2 (95%CI 2.1 - 4.9) for permanent stress and 2.1 (95%CI 1.5 - 2.8) for several periods of stress respectively. More cases experienced depression compared with controls (19.6% vs. 9.3%) and ORs were 2.2 (95%CI 1.9 - 2.6). Subjects with 1, 2 and 3 or more depressive symptoms had increased risk of AMI by 2.1, 2.2 and 2.6 fold, respectively, i.e., more depressive symptoms were associated with higher risks of AMI (P for trend < 0.0001). Women had a greater risk of AMI from depression (OR 3.0, 95%CI 2.2 - 4.0) compared to men (OR 2.0, 95%CI 1.6 - 2.4), P for interaction = 0.0364. Negative life events in subjects were associated with increased risk of AMI, OR 1.7 (95%CI 1.4 - 2.0) for one event and 1.8 (95%CI 1.3 - 2.4) for two or more events. High levels of controllability of life circumstances reduced the risk for AMI (OR 0.8, 95%CI 0.7 - 1.0).
Conclusions: Several psychological factors were closely associated with increased AMI risk among Chinese population. Psychological stress had a greater AMI risk in men but depression was more significant among women.