Impact of visceral adipose tissue and subcutaneous adipose tissue on insulin resistance in middle-aged Japanese.

AIM The enlargement of visceral adipose tissue (VAT) is considered to mediate the close relationship between obesity and insulin resistance. We aimed to determine whether a stronger association of VAT compared to subcutaneous adipose tissue (SAT) with insulin resistance could be confirmed and generalized in non-diabetic Japanese men and women. METHODS Participants were 912 non-diabetic Japanese (636 men and 276 women, mean age 52.4±7.0 years, and mean BMI 24.9±3.1 kg/m(2)). VAT and SAT were measured through the use of computed tomography scanning. Homeostatic model for the assessment of insulin resistance (HOMA-IR) and Matsuda insulin sensitivity index (ISI) were calculated based on results from the oral glucose tolerance test. RESULTS For both genders, subjects in higher tertiles of SAT as well as VAT showed significantly higher levels of HOMA-IR and lower levels of Matsuda ISI (p<0.001). In multiple regression analyses with VAT and SAT included in the model, only VAT, but not SAT, was independently associated with Matsuda ISI in women (p<0.001), whereas both SAT and VAT were independently associated with HOMA-IR and with Matsuda ISI in men (p<0.001). When VAT and waist circumference were jointly included in the model, only VAT, but not waist circumference, was independently associated with Matsuda ISI in women (p<0.001) but not in men. CONCLUSION VAT had a stronger association with insulin resistance than SAT or waist circumference in women but not in men. BMI showed a comparable association with insulin resistance to VAT in this population.