Psychological distress as a risk factor for coronary heart disease in the Whitehall II Study

BACKGROUND: Psychiatric disorder and psychological distress are increasingly recognized as risk factors for coronary heart disease (CHD). Elucidation of the mechanisms of these associations has implications for prevention. This study aims to confirm the association between psychological distress and CHD and examine if it could be explained by other factors such as health behaviours, social isolation and low control at work. METHODS: A prospective occupational cohort study of London-based civil service employees (Whitehall II Study) with baseline data collected from 1985-1988 with a 5-year follow-up. The participants were male and female middle-aged civil servants working in 20 Government Departments; 73% of eligible employees attended baseline screening. Psychological distress measured by the General Health Questionnaire (GHQ) at baseline was used to predict incidence of self-reported CHD and possible and probable electrocardiographic (ECG) abnormalities during follow-up. RESULTS: In men, baseline psychological distress was associated with an increased incidence of overall self-reported CHD (odds ratios OR = 1.83, 95% CI : 1.5-2.3) and ECG abnormalities (OR = 1.51, 95% CI : 1.1-2.1), after adjustment for age, employment grade and length of follow-up. In women, baseline psychological distress was also associated with an increased incidence of CHD (OR = 1.60, 95% CI : 1.2-2.1), but not with ECG abnormalities. Adjustment for health behaviours, marital status, social networks and work characteristics reduced the risks for incident CHD by 12% in men and by 10% in women; for ECG abnormalities these adjustments increased the risk in men by 16% and had little effect in women. CONCLUSIONS: The experience of psychological distress confers increased risk of CHD in men that is not explained by health behaviours, social isolation or work characteristics. The increased risk of CHD associated with psychological distress is not consistently demonstrated in women.