Introduction Healthy lifestyle choices, such as weight control through a balanced diet and regular physical activity, play a key role in chronic disease prevention. Underlying socioeconomic factors may mediate disease risk, but are often neglected. We aimed to investigate whether either educational level or occupational social class influences the incidence of diabetes, myocardial infarction, stroke and cancer, independently from a healthy lifestyle.

Methods We prospectively examined the associations of both indicators with incident chronic diseases in 23 453 participants, aged 35–65 of the EPIC-Potsdam Study. Age- and multivariate adjusted HRs (HR, 95% CI) were calculated. An additional systematic literature search aimed to identify how different socioeconomic indicators were related to the selected diseases.

Results Although inequalities in a healthy lifestyle were found among men and women for both indicators, variations in their direction and magnitude for incident disease risks occurred. Diabetes incidence was inversely associated with both indicators in multivariate models, but adjustment for Body mass index substantially attenuated the associations. Middle-educated women had a lower risk for myocardial infarction (HR 0.39, 018–0.84), but a higher risk for stroke (HR 2.03, 1.07–3.83), in fully-adjusted models. Protective effects against cancer were shown for semiprofessional men and unskilled women, but not for education. Also the results of the literature search showed that different socioeconomic indicators appeared to vary in their associations to chronic disease risk.

Conclusions Educational level and occupational social class varied in their influence on incident chronic diseases, but are less important predictors for disease risk in the EPIC-Potsdam study.