Social inequality and incidence of and survival from cancer in a population-based study in Denmark, 1994-2003: Background, aims, material and methods.

The purpose of this register-based study was to identify variations in cancer incidence and survival after cancer in Denmark on the basis of a range of socioeconomic, demographic and health-related indicators. The indicators were level of education, disposable income, affiliation to the work market, social class, housing tenure, size of dwelling, cohabitation status, type of district, ethnicity, Charlson comorbidity index, depression and schizophrenia measured at the individual level on an annual basis. The study population comprised all Danish residents born between 1925 and 1973 and aged >or=30 years, who were followed up for cancer incidence in 1994-2003 and for survival in 1994-2006. The study was based on 3.22 million persons, yielding almost 26 million person-years and 147,973 cancers. In this paper, we provide a detailed description of the indicators and the statistical methods, and we discuss the strengths and limitations of our approach.