Relationships between body fat accumulation, aerobic capacity and insulin resistance in Japanese participants

Aim: This study evaluated the relationships between body fat accumulation, aerobic capacity and insulin resistance (HOMA-IR) in 61 Japanese participants. Method: The participants were middle-aged to elderly (age: 33-73; BMI: 21.6-38.5). Body fat mass (FM) was evaluated by hydrostatic weighing. Computed tomography was used to evaluate visceral and subcutaneous fat areas (VFA and SFA), liver to spleen ratio (L/S), and low-density muscle area (LDMA). To assess aerobic capacity, VO2 at the lactate threshold (VO2@LT) and VO2 (peak) were measured using a bicycle ergometer. Results: FM, VFA, SFA, LDMA and L/S significantly correlated with HOMA-IR, but VO2@LT and VO2 (peak) did not. Analysis of covariance after adjustment for VFA or other body fat distribution and aerobic capacity showed that HOMA-IR had a significant linear trend across the tertile groups of L/S. However, for FM, VFA, SFA, LDMA and VO2@LT or VO2 (peak), no significant trend was observed between the tertiles and insulin resistance. Conclusions: Ectopic fat deposition in the liver may influence insulin resistance independently of other body fat accumulation and aerobic capacity in Japanese participants. (C) 2011 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.