Socioeconomic gradients in the prevalence of cardiovascular disease in Scotland: the roles of composition and context.

OBJECTIVE To investigate whether occupational social class and area deprivation are independently associated with the prevalence of cardiovascular disease (CVD) conditions after adjustment for smoking status. DESIGN Stratified multistage random sample analysed using multilevel logistic regression. PARTICIPANTS 8804 adults aged 18-74 at time of interview in 1998-1999, clustered in 312 small areas. The outcome considered was a self report of doctor diagnosis of one of a number of CVD conditions. The survey also provided information concerning the respondent's occupational social class and current smoking status. The Carstairs score (based on the 1991 census) was used to describe small area deprivation. MAIN RESULTS The gradient in CVD prevalence across individual social class was attenuated and became insignificant when area deprivation was considered. The aggregation of individual social class and smoking to the area level increased the correlation with disease prevalence at the individual level. CONCLUSIONS Although there is a relation between socioeconomic status and CVD prevalence in Scotland, the relation is dominated by area deprivation. When externally validated deprivation measures are not available, aggregated individual characteristics may show a contextual (as compared with compositional) relation.