Body fat distribution and cardiovascular risk in normal weight women. Associations with insulin resistance, lipids and plasma leptin

OBJECTIVE: To systematically examine the correlations between insulin resis tance, plasma leptin concentration, obesity and the distribution of fat ass essed by anthropometry and magnetic resonance imaging in Asian women. DESIGN: A cross sectional study of non-diabetic, normal weight women. SUBJECTS: Twenty-one healthy women aged 38.8 y (s.d. 11.7) and BMI 22.6 kg/ m(2) (s.d, 2.3). MEASUREMENTS: Intraperitoneal, retroperitoneal and subcutaneous abdominal f at volume was assessed by magnetic resonance imaging. Anthropometric data w ere collected. Total fat mass was assessed by bioelectric impedance analysi s. Easting serum lipids, insulin and plasma leptin were assayed. RESULTS: Generalized obesity correlated with subcutaneous abdominal fat mas s (r = 0.83, P < 0.001), but not with intra-abdominal fat mass. Both intrap eritoneal fat mass and retroperitoneal fat mass increased with age (r = 0.5 8, P = 0.005 and r = 0.612, P = 0.003, respectively). Abdominal subcutaneou s fat mass was the most important determinant of insulin resistance and pla sma leptin, Of the serum lipids, only fasting triglyceride correlated signi ficantly with the waist-to-hip ratio. CONCLUSIONS: It is possible that the large size of the subcutaneous depot c ompared to the intra-abdominal depot overwhelms any metabolic differences b etween adipose tissue from these two sites, resulting in the stronger corre lation between insulin resistance and subcutaneous abdominal fat mass rathe r than intra-abdominal fat mass. On the other hand, the distribution of fat between subcutaneous fat depots may be important in the metabolic syndrome given the correlation of fasting triglyceride with waist to hip ratio but not with abdominal fat. However, the study population was small, younger an d leaner compared to previous studies and we may not be able to generalize these results to all segments of the population. We confirm that subcutaneo us fat mass is the major determinant of plasma leptin.