Abstract
CONTEXT: Increased high-density lipoprotein cholesterol (HDL-C) is common in type 1 diabetes (T1D) and is associated both with hyperadiponectinemia and with elevated lipoprotein lipase activity (LPL). Because adiponectin has been shown to increase LPL expression, elevated LPL may link the hyperadiponectinemia in T1D with increased HDL. OBJECTIVE: The purpose of this study was to determine whether LPL activity accounts for the association between adiponectin and HDL in T1D. DESIGN, PARTICIPANTS, AND SETTING: A cohort of 127 patients with T1D attending the Diabetes Clinic at the University of Miami and 103 healthy control subjects were recruited. MAIN OUTCOME MEASURE: HDL-C and adiponectin were measured in the full cohort and in a subgroup, HDL subfractions were obtained by ultracentrifugation, and LPL and hepatic lipase were measured in postheparin plasma. RESULTS: Total HDL-C and the lowest density HDL subfraction, apolipoprotein A-I, LPL activity, and adiponectin levels were higher in subjects with T1D than in control subjects (P < .05). Both adiponectin and LPL activity were directly associated with total HDL-C and its lowest density subfraction, but adiponectin and LPL were not correlated (P = 0.13). Adiponectin alone explained 11.6% and adiponectin plus LPL explained 23.8% of the HDL-C variance. In a multivariate model, adiponectin remained an independent predictor of HDL-C along with LPL and serum creatinine, explaining together 27% of HDL-C variance. CONCLUSIONS: Adiponectin was strongly associated with HDL-C in T1D, suggesting that hyperadiponectinemia is linked to the elevated HDL-C in this population. However, this relationship is independent of the association between LPL and HDL-C. Thus, elevated adiponectin and LPL activity are independently related to increased HDL-C in T1D.