Lower educational level is a predictor of incident type 2 diabetes in European countries: the EPIC-InterAct study

Background Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases worldwide. In high-income countries, low socioeconomic status seems to be related to a high incidence of T2DM, but very little is known about the intermediate factors of this relationship. Method We performed a case-cohort study in eight Western European countries nested in the EPIC study (n¿=¿340¿234, 3.99 million person-years of follow-up). A random sub-cohort of 16¿835 individuals and a total of 12¿403 incident cases of T2DM were identified. Crude and multivariate-adjusted hazard ratios (HR) were estimated for each country and pooled across countries using meta-analytical methods. Age-, gender- and country-specific relative indices of inequality (RII) were used as the measure of educational level and RII tertiles were analysed. Results Compared with participants with a high educational level (RII tertile 1), participants with a low educational level (RII tertile 3) had a higher risk of T2DM [HR: 1.77, 95% confidence interval (CI): 1.69–1.85; P-trend