Relation of plasma lipids to insulin resistance, nonesterified fatty acid levels, and body fat in men from three ethnic groups: relevance to variation in risk of diabetes and coronary disease.

Afro-Caribbean men in the United Kingdom have a favorable lipoprotein profile and are at low risk of coronary heart disease (CHD) compared with Europeans and South Asians, but are at high risk of non-insulin-dependent diabetes mellitus (NIDDM) compared with Europeans. To investigate these differences, a cross-sectional comparison was undertaken for measures of lipoprotein metabolism, body composition, and insulin's glucoregulatory and antilipolytic actions in 92 healthy men (42 to 61 years) of Afro-Caribbean, South Asian, or European origin. Afro-Caribbean men were more insulin-resistant than Europeans (insulin sensitivity [Si], 1.96 v3.01 min(-1) x microU(-1) x mL, P < .01). They nevertheless had a more favorable lipoprotein profile, with lower levels of very-low-density lipoprotein (VLDL) cholesterol (0.21 v 0.40 mmol/L, P < .01) and triglycerides (0.34 v 0.74 mmol/L, P < .01), lower serum total triglycerides, higher high-density lipoprotein 2 (HDL2) cholesterol, and larger low-density lipoprotein (LDL) particle size. These differences were not accounted for by differences in nonesterified fatty acid (NEFA) levels, the sensitivity of suppression of NEFA levels to insulin, or body composition. South Asians were also more insulin-resistant than Europeans but had a less favorable lipoprotein profile. Afro-Caribbean men in the United Kingdom are as insulin-resistant as South Asian men but less susceptible to the lipid disturbances that characteristically accompany insulin resistance. This favorable lipid pattern may relate to more effective VLDL metabolism rather than a reduced supply of NEFA as substrate for triglyceride synthesis.