Ethnic differences in serum lipoproteins and their determinants in South African women.

The objective of the study was to characterize ethnic differences in lipid levels and low-density lipoprotein (LDL) particle size and subclasses in black and white South African women and to explore the associations with insulin sensitivity (S(I)), body composition, and lifestyle factors. Fasting serum lipids and LDL size and subclasses, body composition (dual-energy x-ray absorptiometry), and S(I) (frequently sampled intravenous glucose tolerance test) were measured in normal-weight (body mass index <25 kg/m(2)) black (n = 15) and white (n = 15), and obese (body mass index >30 kg/m(2)) black (n = 13) and white (n = 13) women. Normal-weight and obese black women had lower triglycerides (0.59 +/- 0.09 and 0.77 +/- 0.10 vs 0.89 +/- 0.09 and 0.93 +/- 0.10 mmol/L, P < .05) and high-density lipoprotein cholesterol (1.2 +/- 0.1 and 1.1 +/- 0.1 vs 1.7 +/- 0.1 and 1.6 +/- 0.3 mmol/L, P < .01) than white women. The LDL particle size was not different, but obese black women had more LDL subclass IV (17.3% +/- 1.0% vs 12.5% +/- 1.0%, P < .01). In white women, triglycerides and LDL particle size correlated with S(I) (P < .01), whereas cholesterol levels correlated with body fat (P < .05). Low socioeconomic status, low dietary protein intake, and injectable contraceptive use were the major determinants of unfavorable lipid profiles in black women. Black women had lower triglyceride and high-density lipoprotein cholesterol levels and more small dense LDL particles than white women. The major determinants of serum lipids in black women were socioeconomic status and lifestyle factors, whereas in white women, S(I) and body composition most closely correlated with serum lipids.