Social class, risk factors, and stroke incidence in men and women: a prospective study in the European prospective investigation into cancer in Norfolk cohort.

BACKGROUND AND PURPOSE The purpose of this study was to investigate the association between occupational social class and stroke incidence and the extent to which classical, lifestyle, and psychosocial risk factors may explain such relationships. METHODS A prospective population study was conducted of 22488 men and women aged 39 to 79 years living in the general community in Norfolk, UK, recruited in 1993 to 1997 and followed up for stroke incidence to 2007. RESULTS An inverse relationship was observed between social class and stroke incidence with an age- and sex-adjusted hazard ratio for social Class V compared with I of 2.62 (95% CI, 1.63 to 4.22; P=0.001). Adjusting for classical (systolic blood pressure, total blood cholesterol, smoking, history of diabetes, and body mass index), lifestyle (plasma vitamin C levels, alcohol intake, and physical activity), and psychosocial (5-item version of the Mental Health Inventory) risk factors had little effect, and a socioeconomic differential was still apparent: hazard ratio for social Class V compared with I of 2.55 (95% CI, 1.34 to 4.85, P=0.004 for comparison of V to I). CONCLUSIONS Stroke incidence increased with lower social class in both men and women. Adjustment for a comprehensive range of classical, lifestyle, and psychosocial risk factors did not explain the socioeconomic differential in stroke incidence. If we are to reduce inequalities in health, further understanding of the mechanisms underlying the association is needed.