The social class gradient in cardiovascular disease: A prospective study of Finnish men

Much remains to be understood about the inverse relationship between social class (SES) and health. Data from the Kuopio Ischemic Heart Disease Risk Factor Study were used to estimate the associations between childhood social class, adult income, education, occupation, all-cause, and cardiovascular mortality, acute myocardial infarction (AMI), and carotid intima-media thickness (IMT), in a population based sample of 2682 Finnish men. The results show (1) an increased mortality risk in low compared to high adult income groups not explained by childhood SES, (2) a strong, graded association between SES and atherosclerosis was seen both in the early stages of atherosclerosis, as well as in a healthy subgroup, and (3) a marked attenuation of the relationship between SES and both mortality and AMI risk after account was taken of 23 known risk factors. These findings indicate how a lifecourse approach to social class differences in adult health requires an understanding of the broader social and economic context in which individual socioeconomic life trajectories are determined. To a large extent, the results show the mechanisms of how SES effects mortality, IMT and AMI, but the results do not shed any light on why SES is associated with these biological, behavioral, and psychosocial risk factors. If lower SES acts as a powerful force in the adoption of poor dietary habits, or influences behaviors such as smoking and physical activity, or if poorer people are more likely to be hopeless or depressed, then understanding the relationship between SES and these outcomes must include more than an estimate of the extent to which its effect is carried by known biological, behavioral, psychological and social risk factors. The field of public health has focused on these disease mechanisms as the reasons for the association between SES and disease, and has consequently advocated behavioral interventions which "target" lower SES groups. If differences in social class are at the beginning of the causal pathway for disease, then surely interventions which directly reduce social class differences are the most primary of all prevention strategies.