Demographic and behavioural correlates of high density lipoprotein cholesterol. An international comparison between Northern Italy and the United States

Recently published results of longitudinal follow-up studies conducted in the US have identified high density lipoprotein (HDL)-cholesterol as an independent and strong predictive factor for coronary heart disease (CHD). Some inconsistencies in this association have been found when geographical comparisons were done, which could be explained by hypothesizing differences in population HDL-cholesterol determinants. We carried out a comparative analysis of demographic and behavioural correlates of HDL-cholesterol between Northern Italy and the US, two countries with well-known differences in CHD risk and HDL-cholesterol levels. The study was conducted on representative samples of these two countries IMONICA Project-Area Brianza for Northern Italy and NHANES II for the US) and used comparable methodologies for data collection and statistical analysis. Results indicate that gender, age, body mass, cigarette smoking and alcohol consumption are independently associated with HDL-cholesterol in both populations; physical activity is positively, but not significantly, associated with HDL-cholesterol mean levels, and education achievement is independently associated only in the American sample. The comparison of the magnitude of the multivariate regression coefficients between the two studies suggests similar functional relationships for most of the correlates considered. The small, albeit significant, discrepancies found for body mass and smoking status could be related either to some methodological inconsistencies between the two surveys, or to possible effects of other covariates, not available to be tested in this study, like dietary habits. Moreover, HDL-cholesterol mean level differences between populations could be also due to differences in the prevalence of the examined correlates.