Abstract:Objective: The regulation of triglyceride (TG) metabolism may be affected by many factors including: race/ethnicity, body composition, body fat distribution, insulin action, and the activity of the lipoprotein lipase (LPL) enzyme. This study was designed to identify the independent effects of body composition, body fat distribution, insulin action, and LPL genetic variation on TG and HDL-C concentration. Subjects: The study consisted of premenopausal European American (EA) (n=114) and African American (AA) (n=140) women. Measurements: Body composition was measured by dual-energy X-ray absorptiometry (DXA), intra-abdominal adipose tissue (IAAT) by computed tomography (CT), insulin sensitivity (SI) and the acute insulin response to glucose (AIRg) by intravenous glucose tolerance test, median household income by zip-code. An estimate of individual genetic admixture was obtained from the genotyping of 85 ancestry informative markers and used to control for population stratification. Multiple linear regression analyses were used to identify contributions of body composition, IAAT, SI, AIRg, African genetic admixture, and LPL polymorphisms to TG and HDL-C. Results: AA had lower TG and higher HDL-C than EA. African genetic admixture, IAAT, AIRg, SI, and RS285 were significantly and independently related to TG concentration. SI was the only independent contributor to HDL-C. RS1800590 was not associated with variation in TG or HDL. Conclusion: Triglyceride concentration appears to be multifactorial in origin and emanates in part from variance in LPL RS285. Future investigations are necessary to understand the mechanisms through which gene polymorphisms, body fat distribution, and insulin action influence the lipid profile.

Bone mineral density (BMD) and fracture risk are elevated in adults with impaired fasting glucose (IFG) or type 2 diabetes mellitus (T2D). This study aimed to compare bone health among Inuit women with IFG, T2D and normoglycemia. The study included Inuit women (≥40 y) with IFG (n = 57), T2D (n = 72) or normoglycemia (n = 340) from the International Polar Year Inuit Health Survey 2007-2008 in Canada. Distal one-third forearm BMD (FaBMD) was measured using a peripheral instantaneous x-ray imager. Anthropometry, fasting plasma glucose (FPG), serum adiponectin, leptin and 25-hydroxyvitamin D (25(OH)D) were measured. Traditional food intakes were surveyed. Data were analysed using mixed model ANOVA and regression models. The median age was 53 (IFG: IQR 48, 67) y and 56 (T2D: IQR 49, 63) y. Compared to normoglycemic women, FaBMD and T-scores were significantly lower in women with T2D, but not with IFG. Frequency of marine mammal intakes (ß = 0.145; 95%CI: 0.018, 0.053, p = 0.0001) positively related to FaBMD. The odds ratio of having a T-score consistent with osteoporosis was lower among women with T2D and higher BMI, while aging increased the risk. Although T2D associates with lower BMD among Inuit women, risk of osteoporosis is tempered, possibly by maintenance of a traditional lifestyle.