Do pre-employment influences explain the association between psychosocial factors at work and coronary heart disease? The Whitehall II study

Objectives: To examine whether the association between psychosocial factors at work and incident coronary heart disease (CHD) is explained by pre-employment factors, such as family history of CHD, education, paternal education and social class, number of siblings and height. Methods: A prospective cohort study of 6435 British men aged 35-55 years at phase 1 (1985-1988) and free from prevalent CHD at phase 2 (1989-1990) was conducted. Psychosocial factors at work were assessed at phases 1 and 2 and mean scores across the two phases were used to determine long-term exposure. Selected pre-employment factors were assessed at phase 1. Follow-up for coronary death, first non-fatal myocardial infarction or definite angina between phase 2 and 1999 was based on clinical records (250 events, follow-up 8.7 years). Results: The selected pre-employment factors were associated with risk for CHD: HRs (95% CI) were 1.33 (1.03 to 1.73) for family history of CHD, 1.18 (1.05 to 1.32) for each quartile decrease in height and 1.16 (0.99 to 1.35) for each category increase in number of siblings. Psychosocial work factors also predicted CHD: 1.72 (1.08 to 2.74) for low job control and 1.72 (1.10 to 2.67) for low organisational justice. Adjustment for preemployment factors changed these associations by 4.1% or less. Conclusions: In this occupational cohort of British men, the association between psychosocial factors at work and CHD was largely independent of family history of CHD, education, paternal educational attainment and social class, number of siblings and height.