Objectives: Data from the Western Collaborative Group Study were used to determine the extent to which the inverse association between socioeconomic status (SES) and mortality can be explained by risk factors for major causes of mortality.
Methods: The relation of education and income to subsequent mortality was studied in 3154 employed, middle-aged men over 22 years of follow-up.
Results: Over the follow-up period, 584 (18.5%) men died, 214 (6.8%) from coronary heart disease and 70 (2.2%) from lung cancer. A significant inverse association with systolic blood pressure, serum cholesterol, and smoking was found only for education. For education, adjustment for risk factors reduced the relative risk for coronary heart disease mortality from 1.80 (95% confidence interval = 1.33, 2.44) to 1.54 (1.13, 2.09), for lung cancer mortality from 1.60 (0.95, 2.70) to 1.38 (0.81, 2.34), and for all-cause mortality from 1.49 (1.09, 1.13) to 1.33 (1.12, 1.60). For income, adjustment for risk factors did not change relative risk for mortality from coronary heart disease (1.27 [0.97, 1.66]) and all causes (1.21 [1.03, 1.43]), but it did increase the relative risk for lung cancer mortality from 1.68 (1.05, 2.68) to 1.83 (1.13, 2.96).
Conclusions: In middle-aged, employed men, the association between SES and mortality is partially but not completely accounted for by major risk factors for mortality.