Lipoprotein particle distribution and size, insulin resistance, and metabolic syndrome in Alaska Eskimos: The GOCADAN study

Background Metabolic syndrome (MS) is associated with dyslipidemia, and insulin resistance (IR) may be a main determinant of this dyslipidemia. Objective To determine how lipoprotein particle concentration and size are related to MS and IR in a population-based sample of Alaska Eskimos. Design Participants underwent a physical exam, personal interview, collection of biological specimens, and diagnostic tests. Setting This study was conducted in the Norton Sound region of Alaska. Participants One thousand one hundred fifty-eight Inupiat Eskimo adults (women = 653, men = 505). Main outcome measures Lipoprotein particle profile was evaluated by nuclear magnetic resonance (NMR) and related to presence of MS and level of IR. Results Participants with MS had (a) significantly higher concentrations of all VLDLs and a larger VLDL size (women, p = 0.007; men, p = 0.0001); (b) higher concentrations of small LDL (women, p < 0.0001; men, p = 0.09) and lower concentrations of large LDL (women, p < 0.0001), leading to a smaller overall LDL size (women, p < 0.0001; men, p < 0.05); (c) significantly lower concentrations of large HDL (both genders, p < 0.0001) and an increase in intermediate (women, p < 0.05) and small HDL (women, p < 0.0001; men, p < 0.004). Lipoprotein profile with increasing HOMA-IR resembled that of individuals with MS. Conclusions In this population MS is characterized by lipoprotein distribution and size abnormalities independent of obesity, age, and other cardiovascular risk factors, including lipid concentration. IR seems the major determinant.