Black and white offspring of parents with type 2 diabetes develop prediabetes at a similar high rate of approximately 11% per year. Therefore, close surveillance, with prompt intervention to prevent dysglycemia, is warranted in persons with parental diabetes.

The POP-ABC study has successfully enrolled healthy African-American and Caucasian adults with parental type 2 diabetes mellitus. The study will generate novel data on incidence rates and predictors of prediabetes, and clarify the role of race/ethnicity on early dysglycemia.

BackgroundAdiponectin levels display ethnic disparities, and are inversely associated with the risk of type 2 diabetes (T2DM). However, the association of adiponectin with prediabetes risk in diverse populations has not been well-studied. Here, we assessed baseline adiponectin levels in relation to incident prediabetes in a longitudinal biracial cohort.Research design and methodsThe Pathobiology of Prediabetes in A Biracial Cohort study followed non-diabetic offspring of parents with T2DM for the occurrence of prediabetes, defined as impaired fasting glucose and/or impaired glucose tolerance. Assessments at enrollment and during follow-up included a 75 g oral glucose tolerance test, anthropometry, biochemistries (including fasting insulin and adiponectin levels), insulin sensitivity and insulin secretion. Logistic regression was used to evaluate the contribution of adiponectin to risk of progression to prediabetes.ResultsAmong the 333 study participants (mean (SD) age 44.2 (10.6) year), 151(45.3%) were white and 182 (54.8%) were black. During approximately 5.5 (mean 2.62) years of follow-up, 110 participants (33%) progressed to prediabetes (N=100) or T2DM (N=10), and 223 participants (67%) were non-progressors. The mean cohort adiponectin level was 9.41+5.30 μg/mL (range 3.1–45.8 μg/mL); values were higher in women than men (10.3+5.67 μg/mL vs 7.27+3.41 μg/mL, p<0.0001) and in white than black offspring (10.7+5.44 μg/mL vs 8.34+4.95 μg/mL, p<0.0001). Adiponectin levels correlated inversely with adiposity and glycemia, and positively with insulin sensitivity and high-density lipoprotein cholesterol levels. Baseline adiponectin strongly predicted incident prediabetes: the HR for prediabetes per 1 SD (approximately 5 μg/mL) higher baseline adiponectin was 0.48 (95% CI 0.27 to 0.86, p=0.013).ConclusionsAmong healthy white and black adults with parental history of T2DM, adiponectin level is a powerful risk marker of incident prediabetes. Thus, the well-known association of adiponectin with diabetes risk is evident at a much earlier stage in pathogenesis, during transition from normoglycemia to prediabetes.

Background-Dietary and exercise data are frequently recorded in clinical research, but their correlation with metabolic measures needs further evaluation.Objective-We examined the association of food and exercise habits with body size, lipid profile, and glycemia in a prospective biracial cohort.Address for correspondence and reprints: Samuel Dagogo-Jack, MD, Division of Endocrinology, Diabetes and Metabolism, 920 Madison Avenue, Suite 300A, University of Tennessee Health Science Center, Memphis, TN 38163, sdj@uthsc.edu. Conflicts of Interest:The authors have no relevant conflict of interest to disclose with regard to the content of this manuscript. DISCLOSURE STATEMENTThe authors have no relevant conflict of interest to disclose with regard to the content of this manuscript. AUTHORS' CONTRIBUTIONSS.D.-J., as the principal investigator and developed the study concept and design, and wrote the manuscript; A.B. collected data, reviewed and revised the manuscript; E.A.O.A. collected data, reviewed and revised the manuscript; S.E. collected data, reviewed and reviewed the manuscript; I.O. collected data, reviewed and revised the manuscript; S.E. collected data, conducted statistical analysis and reviewed the manuscript; A.K.G. reviewed and revised the manuscript; J.W. performed statistical analyses; C.E. collected data and reviewed and revised the manuscript. S.D-J. had primary responsibility for final content. All authors read and approved the final manuscript. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 1 POP-ABC Research Group HHS Public Access Conclusions-AmongAfrican-American and Caucasian offspring of parents with T2DM, selfreported dietary and exercise habits correlated with measures of adiposity and dyslipidemia; however, physical activity, but not dietary recall, significantly predicted incident dysglycemia during 5.5 years of follow-up.

Objective A hemoglobin (Hb) A1c range of 5.7%-6.4% has been recommended for the diagnosis of prediabetes. To determine the significance of such “prediabetic” HbA1c levels, we compared glucoregulatory function in persons with HbA1c levels of 5.7%-6.4% and those with HbA1c < 5.7%. Methods We studied 280 nondiabetic adults (142 black, 138 white; mean (± SD) age 44.2 ± 10.6 y). Each subject underwent clinical assessment, blood sampling for HbA1c measurement, and a 75-g oral glucose tolerance test at baseline. Additional assessments during subsequent outpatient visits included insulin sensitivity, using homeostasis model assessment (HOMA)-IR and the hyperinsulinemic euglycemic clamp; insulin secretion, using HOMA-B and frequently samples intravenous glucose tolerance test (FSIVGTT) and disposition index (DI); and measurement of fat mass, using DXA. Results Compared to subjects with HbA1c < 5.7%, persons with HbA1c levels of 5.7%-6.4% were older, and had higher body mass index (BMI) and insulin secretion but similar insulin sensitivity. When the two groups were matched in age and BMI, persons with HbA1c 5.7–6.4% were indistinguishable from those with HbA1c <5.7% with regard to all measures of glycemia glucoregulatory function. Conclusions Unlike glucose-defined prediabetes status, an HbA1c range of 5.7%- 6.4% does not reliably identify individuals with impaired insulin action or secretion, the classical defects underlying the pathophysiology of prediabetes. Thus, HbA1c cannot validly replace blood glucose measurement in the diagnosis of prediabetes. If utilized as a screening test due to convenience, aberrant HbA1c values should be corroborated with blood glucose measurement before therapeutic intervention.