Objective: To determine the magnitude of social inequalities in cancer incidence according to different socioeconomic indicators and to assess the independent role of each indicator.
Methods: Data from the Turin Longitudinal Study and the Piedmont Cancer Registry (1985-1999) were used to analyse the relationship of cancer incidence with three dimensions of individual socioeconomic position (education, occupation, and material living conditions) and with an area-based deprivation index. Multivariate Poisson regression models were used to estimate both relative risks and relative indexes of inequality (RIIs).
Results: Results showed an independent role of all the socioeconomic indicators. The overall gradients of inequalities, expressed by the RIIs for total cancer incidence, varied from 9 to 26% among men; among women, we estimated a 22% protection at the bottom of the educational hierarchy, and a 12% gradient for decreasing ease of living conditions. For most cancer sites, socioeconomic position in early adult life was as important as later socioeconomic position, while the area-based deprivation index played only an additional role.
Conclusions: Different socioeconomic indicators pinpoint to a series of specific risk factors that are related to specific phases of the life course. Individual level data, rather than ecological data, is preferred to accurately monitor social inequalities in cancer risk.