Aims and background: The objectives of the present study were to validate the social stratification variables adopted by the European Prospective Investigation into Cancer and Nutrition (EPIC) by comparing them with data from another independent source and to evaluate the geographic and social distribution of eating habits in the Italian EPIC population.
Methods: The validation of the socioeconomic data collected by the EPIC study was performed with the Turin Longitudinal Study as gold standard and using Cohen's kappa statistics to evaluate the concordance between the studies. We then analyzed food groups based on the consumption of meat and fats, carbohydrates, sweets and alcohol, and on an index of the Mediterranean diet. The standardized scores for each food group were subdivided into quartiles, which were used to compare persons in the extreme quartiles. Analysis of the differences in eating habits by center and by educational level was conducted separately for men and women, calculating the prevalence rate ratios and controlling for age, area of birth and body mass index.
Results: Concordance between the two data sources was high for educational level and low for the social-class index based on occupation. Most of the eating habits considered to be potentially harmful (high consumption of meat or fats and alcohol and low consumption of olive oil and fish) were more frequent in Northern than in Southern Italy. These habits were inversely correlated with educational level, especially in the South.
Conclusions: A significant improvement in health could be obtained in the Italian population if culturally and socioeconomically disadvantaged individuals were to abandon their diet rich in meat and fats, as done by more advantaged persons. In the absence of preventive interventions specifically addressed to disadvantaged groups, it is likely that social inequalities in mortality and morbidity will increase.