Socioeconomic status within social class and mortality: a prospective study in middle-aged British men.

Abstract

It has been suggested that mortality differences between groups in society may be greater than are indicated by social class based on occupation. We have examined the relationship between social class and mortality using home and car ownership as additional indices of socioeconomic status within social class. A prospective study of a cohort of men representative of the social class distribution of middle-aged men in Great Britain. One general practice in each of 24 towns in England, Wales and Scotland. Five years after the initial screening of 7735 men aged 40-59 years, 7262 men (94% of the original cohort) provided information on housing tenure and car ownership by completing a postal questionnaire. Deaths from all causes, cardiovascular, cancer and other non-cardiovascular causes during an average follow-up of 9.8 years (range 8.5-11.0 years) after the postal questionnaire. During the follow-up period there were 946 deaths from all causes among the 7262 men. The lowest mortality rates for all causes, cardiovascular, cancer and other non-cardiovascular causes were seen in non-manual social classes I and II. Manual social classes III and IV+V showed a significant 40% increase in risk of death compared to social classes I+II, even after adjustment for a wide range of risk factors (relative risk [RR] = 1.4, 95% confidence interval [CI]: 1.2-1.7 and RR = 1.4, 95% CI: 1.1-1.7 respectively). Within all social class groups, those owning both home and car showed lower rates than those who owned neither, even after adjustment for a wide range of risk factors and employment status. Compared with social classes I+II owning both home and car, all those not owning home and/or car, in each social group, showed a significant approximately twofold increase in risk of death. Adjusted RR for non-manual I+II = 2.1 (95% CI: 1.5-2.9), non-manual III RR = 2.0 (95% CI: 1.3-2.9), manual III RR = 1.8 (95% CI: 1.4-2.4) and manual IV+V RR = 1.8 (95% CI: 1.3-2.5). Similar relationships were seen in all major geographical regions of Great Britain. Mortality differences within society are greater than indicated by social class based on occupation alone. Irrespective of social class, men with greater material assets have lower rates of mortality from all causes than men less well endowed, independent of a wide range of lifestyle and biological factors. These findings suggest that mortality differences within our society are closely related to relative wealth.