Impact of insulin resistance on lipoprotein subpopulation distribution in lean and morbidly obese nondiabetic women

The purpose of this study was to examine the effects of insulin resistance on the lipoprotein subpopulation distribution of very-low-density, low-dens ity, and high-density lipoproteins (VLDL, LDL, and HDL) in lean and morbidl y obese nondiabetic women. Lean women (body mass index [BMI], 20 to 27 kg/m (2)) stratified by BMI were divided into insulin-sensitive (SL, n = 12) and insulin-resistant (RL, n = 8) groups according to Bergman's minimal model, SI. A group of obese women (BMI, 30 to 53 kg/m(2)), also stratified by BMI , were divided into insulin-sensitive (SO, n = 10) and insulin-resistant (R O, n = 11) groups in a similar fashion, Resistant groups were similar to se nsitive groups (SL v RL and SO v RO) in age, weight, percent body fat, and waist circumference, ie, total and regional adiposity. VLDL, LDL, and HDL s ubpopulation distributions were determined in fasting plasma samples by nuc lear magnetic resonance (NMR) spectroscopy. The average particle sizes of a ll 3 classes of lipoproteins were similar for the SL and RL groups. In cont rast, RO subjects had larger VLDL, smaller LDL, and smaller HDL, than SO su bjects (P < .05), Lower concentrations of large LDL and large HDL were foun d in RO compared with SO subjects (P < .05), In obese women, but not in lea n women, VLDL size was associated with plasma insulin (r = .60, P < .005), while LDL size and HDL size were negatively correlated with plasma insulin (r = -.39, P < .05 and r = -.38, P < .05) and positively correlated with SI (r = .54, P < .01 and r = .42, P < .05). These results suggest that in obe se women, insulin resistance may be involved in the formation of lipoprotei n subpopulation distributions that are associated with vascular disease. Co pyright (C) 2000 by W.B. Saunders Company.