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OBJECTIVE--To examine the influence of glycemic and nonglycemic parameters on HbA1c concentrations in young adults, the majority of whom had normal glucose tolerance. RESEARCH DESIGN AND METHODS--We compared the diagnosis of normal glucose tolerance, prediabetes, and diabetes between a standard oral glucose tolerance test (OGTT; World Health Organization 2006 criteria) and HbA1c concentrations (American Diabetes Association [ADA] 2009 criteria) in 116 young adults (average age 21.6 years) from the Pune Children's Study. We also studied the contribution of glycemic and nonglycemic determinants to HbA1c concentrations. RESULTS--The OGTT showed that 7.8% of participants were prediabetic and 2.6% were diabetic. By ADA HbA1c criteria, 23.3% were prediabetic and 2.6% were diabetic. The negative predictive value of HbA1c was 93% and the positive predictive value was 20% (only 20% had prediabetes or diabetes according to the OGTT; this figure was 7% in anemic participants). Of participants, 34%were anemic, 37%were iron deficient (ferritin<15 ng/mL), 40% were vitamin B12deficient (<150 pmol/L), and 22% were folate deficient (<7 nmol/L). On multiple linear regression analysis, HbA1c was predicted by higher 2-h glucose (R² = 25.6%) and lower hemoglobin (R²= 7.7%). When hematological parameters were replaced by ferritin, vitamin B12, and folate, HbA1c was predicted by higher glycemia (R² = 25.6%) and lower ferritin (R² = 4.3%). CONCLUSIONS--The use of HbA1c to diagnose prediabetes and diabetes in iron-deficient populations may lead to a spuriously exaggerated prevalence. Further investigation is required before using HbA1c as a screening tool in nutritionally compromised populations. [ABSTRACT FROM AUTHOR]

A response by the authors to a commentary on their Pune Maternal Nutrition Study which indicates a lack of association between neonatal birth size and maternal high-density lipoprotein (HDL) levels is presented. They address the claim that the results of their study are unusual. They also discuss the significance of conducting large-scale studies of the influence of maternal lipids on newborn size in different populations and ethnicities.

A response by P. S. Hardikar and colleagues to a letter to the editor about their the article "Spuriously High Prevalence of Prediabetes Diagnosed by HbA1c in Young Indians Partly Explained by Hematological Factors and Iron Deficiency Anemia," in the 2012 issue is presented.