Psychological stress and cardiovascular disease: empirical demonstration of bias in a prospective observational study of Scottish men * Commentary: Psychosocial factors and health---strengthening the evidence base

Abstract

Objectives: To examine the association between self perceived psychological stress and cardiovascular disease in a population where stress was not associated with social disadvantage. Design: Prospective observational study with follow up of 21 years and repeat screening of half the cohort 5 years from baseline. Measures included perceived psychological stress, coronary risk factors, self reported angina, and ischaemia detected by electrocardiography. Setting: 27 workplaces in Scotland. Participants: 5606 men (mean age 48 years) at first screening and 2623 men at second screening with complete data on all measures Main outcome measures: Prevalence of angina and ischaemia at baseline, odds ratio for incident angina and ischaemia at second screening, rate ratios for cause specific hospital admission, and hazard ratios for cause specific mortality. Results: Both prevalence and incidence of angina increased with increasing perceived stress (fully adjusted odds ratio for incident angina, high versus low stress 2.66, 95% confidence interval 1.61 to 4.41; P for trend Conclusions: The relation between higher stress, angina, and some categories of hospital admissions probably resulted from the tendency of participants reporting higher stress to also report more symptoms. The lack of a corresponding relation with objective indices of heart disease suggests that these symptoms did not reflect physical disease. The data suggest that associations between psychosocial measures and disease outcomes reported from some other studies may be spurious. What is already known on this topic Higher psychological stress has predicted coronary heart disease in several observational studies Exposure to stress and heart disease outcomes were often based on self report so that a general tendency to negative perceptions may have generated a spurious association between higher perceived stress and heart disease symptoms What this study adds Perceived stress was strongly related to subjective symptoms of heart disease, including those leading to hospital admission However, stress showed a weakly inverse relation to all objective indices of heart disease: socially advantaged men perceived themselves to be most stressed, and the “protective” effect of stress was probably attributable to residual confounding Suggestions that psychological stress is an important determinant of heart disease may be premature