HDL sphingomyelin determinations in normal individuals and patients with type IV-hyperlipoproteinaemia.

In 138 men and 79 women sphingomyelin values in the supernatant of sera obtained by precipitation of apolipoprotein B-containing lipoproteins ( = high density lipoprotein-sphingomyelin, HDL sphingomyelin) were determined using an enzymatic method. In men, lower HDL sphingomyelin values were obtained (0.22 +/- 0.06 mmol/l) than for women (0.24 +/- 0.05 mmol/l) (p less than 0.05). In both sexes HDL sphingomyelin values were independent of age, with the exception that in men greater than or equal to 55 years, HDL sphingomyelin concentrations were lower. The correlation coefficients calculated for HDL sphingomyelin and hypertriglyceridaemia and relative body weight were lower than the correlation coefficients calculated for the corresponding HDL cholesterol values and both risk factors. In women with hypertriglyceridaemia (greater than or equal to 2.28 mmol/l) HDL sphingomyelin values were lower than those for normotriglyceridaemic women within the same age group, while in male hypertriglyceridaemic patients within the same age group there were no differences in HDL sphingomyelin values in comparison to normotriglyceridaemic male subjects. In both sexes the differences measured between hypertriglyceridaemic and normotriglyceridaemic subjects for HDL sphingomyelin were lower than for the corresponding HDL cholesterol values. The results obtained show that HDL sphingomyelin values are not simply a reflection of HDL cholesterol values.