Individual social class, area-based deprivation, cardiovascular disease risk factors, and mortality: the Renfrew and Paisley study

Objective-To investigate the associations of individual and area-based socioeconomic indicators with cardiovascular disease risk factors and mortality. Design-Prospective study Setting-The towns of Renfrew and Paisley in the west of Scotland. Participants-6961 men and 7991 women included in a population-based cardiovascular disease screening study between 1972 and 1976. Main outcome measures-Cardiovascular disease risk factors and cardiorespiratory morbidity at the time of screening: 15 year mortality from all causes and cardiovascular disease. Results-Both the area-based deprivation indicator and individual social class were associated with generally less favourable profiles of cardiovascular disease risk factors at the time of the baseline screening examinations. The exception was plasma cholesterol concentration, which was lower for men and women in manual social class groups. Independent contributions of area-based deprivation and individual social class were generally seen with respect to risk factors and morbidity. All cause and cardiovascular disease mortality rates were both inversely associated with socioeconomic position whether indexed by area-based deprivation or social class. The area-based and individual socioeconomic indicators made independent contributions to mortality risk. Conclusions-Individually assigned and area-based socioeconomic indicators make independent contributions to several important health outcomes. The degree of inequalities in health that exist will not be demonstrated in studies using only one category of indicator. Similarly, adjustment for confounding by socioeconomic position in aetiological epidemiological studies will be inadequate if only one level of indicator is used. Policies aimed at reducing socioeconomic differentials in health should pay attention to the characteristics of the areas in which people live as well as the characteristics of the people who live in these areas.