Association of body composition and β-cell function in obese females with normal glucose metabolism

Abstract

Objective To explore the relationship between body composition and β-cell function in obese females with normal glucose metabolism. Methods Seventy-five obese women with normal blood glucose and without family history of diabetes were investigated. They were assigned to 4 groups based on body mass index (BMI). Body fat content was measured by dual-energy X-ray absorptiometry (DEXA), and intravenous glucose tolerance test (IVGTT) was performed. The acute insulin response (AIR), the area under the curve (AUC) of insulin (AUCins) and homeostasis model assessment (HOMA) for β-cell function (HOMA2-% B) were calculated. Insulin resistance index(HOMA2-IR) and the ratio of AUCins to AUC of glucose (AUCins/AUCglu) were calculated to assess insulin resistance. Results Women with higher BMI appeared to have more total body fat content and trunk fat content. The similar distribution was also found in other parameters, including the plasma glucose levels at 0 and 10 min, AUCins, AIR, AUCins/AUCglu and the difference of insulin level between 0 and 10 min [INS (10-0)] during IVGTF. AUCins, AIR, AUCins/AUCglu and [INS (10-0)] were positively correlated with the age, BMI,total body fat content and trunk fat content. After adjustment of age, the trunk fat content was independently associated with the AIR in a good linear manner. Conclusion The obese females show change in body composition with more trunk fat content. They show significant insulin resistance with compensated elevation of insulin secretion. Body composition assessment is a valid and more accurate method than BMI and waist circumference in predicting early damaged β-cell function in obese patients. Key words: Obesity; Body fat; Islet β-cell function; Insulin resistance