BACKGROUNDMost 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.

METHODSThis 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.

RESULTSCases 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).

CONCLUSIONSSeveral 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.