Possible criteria for obesity based on insulin resistance in Japanese college athletes

The purpose of this study was to search for possible criteria for obesity in Japanese college student athletes by examining insulin resistance.

The subjects were 219 male college students (mean age 20.4 ± 1.3 years), including 119 athletes who belonged to a university sports team and 100 non-athletic individuals who did not. Fasting blood glucose, hemoglobin A1c (HbA1c), fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) levels were examined in relationship to body mass index (BMI) and waist circumference (WC).

Although none of the subjects had diabetes mellitus, 15 (5 athletes (4.2%) and 10 non-athletes (10.0%)) had insulin resistance with HOMA-IR ≥2.5. HOMA-IR was significantly higher in athletes with BMI ≥27.0 kg/m(2) and non-athletes with BMI ≥25.0 kg/m(2) than in subjects with BMI <25.0 kg/m(2). A similar pattern was seen for WC ≥90 cm in athletes and ≥85 cm in non-athletes. Nearly all athletes with increased insulin resistance had BMI ≥27.0 kg/m(2) and WC ≥90 cm. Among non-athletes, nine of the 10 subjects with insulin resistance had BMI ≥25.0 kg/m(2) and WC ≥85 cm. According to these criteria, the sensitivity and specificity were nearly 100% and 93% for athletes, and 90% and 70% for non-athletes, respectively.

Japanese college athletes may be at risk for increased insulin resistance when BMI exceeds 27.0 kg/m(2) and WC exceeds 90 cm.