The preservation of insulin sensitivity in obese women without diabetes

Abstract

Objective: To assess insulin sensitivity, pancreatic beta-cell function, and compare circulating levels of adiponectin and ghrelin in obese women with and without diabetes. Material and Method: Ninety-nine obese women with a body mass index (BMI) ≥ 25 kg/m2 and age at least 40 years without previous history of diabetes participated in this study. Oral glucose tolerance test was performed in all subjects. Serum for insulin, adiponectin, and ghrelin were obtained at baseline. Data were expressed as mean ± SEM. Results: Oral glucose tolerance test revealed 66 non-diabetic (ND) and 33 diabetic (D) subjects. Despite a similar degree of obesity, women without diabetes had near normal insulin sensitivity (ND, 105.7 ± 6.4%; D, 62.3 ± 5.9%; p < 0.001) and beta cell function (ND, 95.4 ± 3.0%; D, 79.0 ± 6.1%; p < 0.001) as assessed by the HOMA model. Non-diabetic subjects had higher serum adiponectin levels despite similar BMI (ND, 8.3 ± 0.4 mg/ml; D, 6.3 ± 0.4 mg/ml; p < 0.01). Obese subjects with diabetes had lower serum ghrelin levels than obese non-diabetic subjects (ND, 1027.2 ± 32.0 pg/ml; D, 875.1 ± 34.6 pg/ml; p < 0.05). Conclusion: Obese women without diabetes have less pancreatic beta cell dysfunction and higher insulin sensitivity than obese women with diabetes. Higher circulating adiponectin may play protective roles in obese non-diabetic subjects, but the significance of higher ghrelin level should be further explored.