High density lipoprotein cholesterol distribution and predictive power in some Italian populations studies

Nine Italian population samples, for a total of 12,365 males and 8,043 females aged 11 to 84, were examined. The age and sex distribution of HDL-cholesterol levels were calculated for studying its relationship with major cardiovascular risk factors, and for estimating its predictive power on coronary events and on all causes of mortality. Mean values of HDL-cholesterol in the pool of the samples ranged, according to different age groups, from 46.4 to 56.8 mg/dl in males and from 53.7 to 55.8 mg/dl in females. The linear correlation coefficients between HDL-cholesterol and 10 risk factors did not show high levels except those with triglycerides in men aged 20-34 (-0.33) and 35-64 (-0.34). Using the multiple linear regression model the levels of HDL-cholesterol were estimated as a function of the 10 risk factors solving 4 equations (for males, females and for two age groups, 20-34 and 35-64). The factors showing significant coefficients were body mass index (negative), triglycerides (negative), cigarette smoking (negative), alcohol consumption (positive), physical activity (positive), and non-HDL-cholesterol (negative). The Cox model was used for the prediction of coronary death and all causes of death and the logistic function for the prediction of coronary incidence in two of the studies on men aged 46-65 (6 year follow-up) and aged 60-79 (5 year follow-up), and including 5 other factors as possible confounders. Only the univariate prediction of coronary deaths in one study (men aged 46-65) provided a significant coefficient for HDL-cholesterol (t = -2.7624).