Factors associated with insulin resistance and fasting plasma ghrelin levels in adolescents with obesity and family history of type 2 diabetes.

OBJECTIVE: To investigate the changes of insulin resistance and fasting plasma ghrelin levels in adolescents with obesity and family history of type 2 diabetes mellitus (FHD) and analyze its related factors.

METHODS: The study included 159 adolescents aged 13-15 years. Anthropometric- measurements, including height, weight and waist. Blood samples were collected and fasting plasma glucose (FPG), serum lipids, true insulin (TI) and fasting plasma ghrelin were assayed. They were divided into four groups according to body mass index (BMI) and FHD: 40 non-obese adolescents without FHD in group A; 40 overweight and obese adolescents without FHD in group B; 40 non-obese adolescents with FHD in group C; 39 overweight and obese adolescents with FHD in group D.

RESULTS: Group B, C and D had significantly higher levels of HOMA-IR and HOMA-beta index than group A, especially Group D (p<0.01). Group C and D had significantly higher levels of FPG and lower levels of ghrelin than group A (p<0.01). HOMA-IR showed positive correlation with BMI (r=0.445), waist (r=0.435), waist-to-height ratio (WHtR)(r=0.471) (p<0.01). Ghrelin showed negative correlation with FPG (r=-0.339), TI (r=-0.237) and HOMA-IR (r=-0.269) (p<0.01). In multiple linear regression analysis, WHtR (beta=4.925, p=0.000) and FHD (beta=0.492, p=0.000) were significant independent predictors for HOMA-IR. FHD (beta=-289.856, p=0.000) and FPG (beta=-228.203, p=0.001) were significant independent predictors for ghrelin.

CONCLUSION: This study showed that the subjects with FHD and obesity who are predisposed to diabetes have insulin resistance in adolescent stage. The lower ghrelin levels in subjects with FHD may be the result of elevated FPG.