Ethnic disparity in hemoglobin A 1c levels among normoglycemic offspring of parents with type 2 diabetes mellitus

摘要

Objective: To investigate the racial/ethnic disparities in hemoglobin A 1c levels among nondiabetic persons with similar parental history of type 2 diabetes mellitus.Methods: We studied a community-based sample of adult offspring of parents with type 2 diabetes mellitus. Measurements included anthropometry, hematology assessments, serial fasting plasma glucose, oral glucose tolerance testing, plasma insulin, hemoglobin A 1c, insulin sensitivity, and β-cell function, using a homeostasis model assessment.Results: The study included 302 participants (135 white, 167 black). Compared with white participants, black participants had lower fasting plasma glucose levels (91.9 ± 0.51 mg/dL vs 93.6 ± 0.50 mg/dL, P = .015), lower area under the curve of plasma glucose during oral glucose tolerance testing (P = .001), higher body mass index (31.1 ± 0.61 kg/m 2 vs 28.5 ± 0.57 kg/m 2, P = .001), and similar insulin sensitivity and β-cell function. Hemoglobin A 1c was higher in black participants than in white participants (5.68 ± 0.033% vs 5.45 ± 0.028%, P.001). The absolute black-white difference in hemoglobin A 1c level of approximately 0.22% persisted after adjusting for age, hemoglobin, hematocrit, body mass index, waist circumference, fasting plasma glucose, glucose area under the curve, and other covariates.Conclusions: Among healthy offspring of parents with type 2 diabetes mellitus in this study, African American participants had higher hemoglobin A 1c levels than white participants after adjusting for age, adiposity, blood glucose, and known variables. Thus, plasma glucose level is more valid than hemoglobin A 1c for diagnosing prediabetes or diabetes in black persons.