Insulin Resistance during Puberty in Non-obese Japanese Children

We examined whether non-obese Japanese children without diabetes exhibited insulin resistance during puberty. The study subjects were 201 Japanese school students, consisting 95 males and 106 females, aged 11.5 ± 2.6 yr. None of the subjects were obese, with the mean percent of overweight being 0.7 ± 10.5%, or had diabetes at the time of the study. Overnight fasting plasma values of insulin (FIRI) and HOMA-R were measured, with concomitant measurement of the plasma glucose (FPG) levels. The mean FPG, FIRI and HOMA-R values were 89.6 ± 7.3 (70-109) mg/dl, 9.0 ± 3.6 (1.7-24.4) µU/ml and 2.0 ± 0.9 (0.3-5.2), respectively. The mean FIRI value was significantly higher in females than in males (8.3 ± 3.4 vs. 9.6 ± 3.7 µU/ml, p=0.0060). The FIRI and HOMA-R values of the pubertal students were significantly higher compared with those of the prepubertal students (FIRI, 10.0 ± 3.4 vs. 6.5 ± 2.8 µU/ml; HOMA-R, 2.3 ± 0.8 vs. 1.4 ± 0.7; p<0.0001 for both). Similar trends were observed between the two genders. The mean FIRI levels and HOMA-R values were positively correlated with age (FIRI, r=0.280, p<0.0001; HOMA-R, r=0.300, p<0.0001). In conclusion, we demonstrated that the FIRI and HOMA-R values were significantly associated with pubertal development in non-obese Japanese children without diabetes, consistent with the results of studies in white and black children.