Different Associations of Diabetes With β-Cell Dysfunction and Insulin Resistance Among Obese and Nonobese Chinese Women With Prior Gestational Diabetes Mellitus

OBJECTIVE To examine the relative contributions of beta-cell dysfunction and insulin resistance to postpartum diabetes risk among obese and nonobese women with prior gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS We performed a cross-sectional survey 1-5 years after 1,263 women who had GDM gave birth. Polytomous logistic regression models were used to assess the associations of b-cell dysfunction (the lower quartile of HOMA-%beta), insulin resistance (the upper quartile of HOMA-IR), decreased insulin sensitivity (the lower quartile of HOMA-%S), and different categories of BMI with prediabetes and diabetes risk. RESULTS beta-Cell dysfunction, insulin resistance, and decreased insulin sensitivity all were significantly associated with hyperglycemic status across normal weight, overweight, and obese groups, and the patterns of insulin resistance and decreased insulin sensitivity were similar. BMI was inversely associated with b-cell dysfunction and positively associated with insulin resistance across normal glucose, prediabetes, and diabetes categories. Compared with women with normal glucose and weight, obese women with normal glucose had increased b-cell secretory function (odds ratio [OR] 0.09 [95% CI 0.02-0.37]) and insulin resistance (OR 17.4 [95% CI 9.47-31.9]). Normal weight diabetic women displayed the most b-cell dysfunction (OR 13.6 [95% CI 4.06-45.3]), whereas obese diabetic women displayed the highest insulin resistance (OR 45.8 [95% CI 18.5-113]). CONCLUSIONS For women with prior GDM, b-cell dysfunction had more pronounced contribution to postpartum diabetes among nonobese subjects, whereas insulin resistance contributed more to postpartum hyperglycemia among obese subjects.