Does the association between self-rated health and mortality vary by social class?

Self-rated health (SRH) predicts future mortality. Individuals in different social classes with similar physical health status may have different reference levels and criteria against which they judge their health, therefore the SRH-mortality relationship may vary according to social class. We examine the relationship between SRH and mortality by occupational social class in a prospective study of 22,457 men and women aged 39-79 years, without prevalent disease, living in the general community in Norfolk, United Kingdom, recruited using general practice age-sex registers in 1993-1997 and followed up for an average of 10 years. As expected, SRH was related to subsequent mortality. The age and sex adjusted hazard ratio for mortality for those with poor compared to those with excellent SRH was 4.35 (95% confidence interval 3.38-5.59, P<0.001). The prevalence of poor or moderate SRH was higher in manual than in non-manual classes. However, SRH was similarly related to mortality in manual and non-manual classes: when non-manual classes are compared with manual classes for each category of SRH, the 95% confidence intervals for the mortality hazard ratios overlap. There was no evidence of an interaction between social class and SRH in either men or women. Thus in this population, SRH appears to predict mortality in a similar manner in non-manual and manual classes.