Low fasting triglycerides: hallmark of the healthy large hip?

Body fat distribution modulates risk for type 2 diabetes mellitus. We evaluated potentially involved metabolic risk factors. In a population of 282 male and 157 female healthy subjects (data from the San Antonio and the European Group of Insulin Resistance (EGIR) study cohorts), we evaluated associations between body fat distribution (assessed by waist and hip circumference) and parameters of lipid- and glucose metabolism, including clamp measurements of insulin sensitivity. After stratification for BMI, fasting triglycerides were lower in the presence of a large hip, and higher in a large waist. Persons with the largest BMI (3rd tertile) showed a difference in triglyceride levels of 1.5 vs. 2.4 mmol/l in large vs. small hip circumference groups (P < 0.038), and a difference of 1.5 vs. 1.2 mmol/l in large vs. small waist circumference groups (P < 0.025). A similar analysis did not reveal a difference in insulin sensitivity. Linear regression analyses confirmed the findings; they revealed negative associations between triglycerides and hip, and (for women borderline statistically significant) positive associations between triglycerides and waist, after adjustment for BMI, mutual confounding, and age (beta +/- s.e.; men: -0.48 +/- 0.005, P < 0.001, and 0.21 +/- 0.005, P < 0.05; women: -0.78 +/- 0.007, P < 0.001, and 0.24 +/- 0.005, P < 0.065), respectively. Linear regression analyses revealed similar opposite associations with high-density lipoprotein (HDL)-cholesterol, though not with glucose, insulin, or insulin sensitivity as measured with the clamp method. In our study population of healthy persons, body fat distribution is associated with fasting triglycerides and HDL-cholesterol, and not with insulin sensitivity. Metabolic risk of unfavorable body fat distribution may be modulated by lower triglyceride storage capacity.