Geographic and Ethnographic Variations of Hemoglobin A1C

Around the world, approximately 9% of adults are currently living with type 2 diabetes mellitus (T2DM).1 In the United States, 50% of the population may suffer from undiagnosed diabetes, and in other countries, the percentage could be higher. For this reason, it is important to establish worldwide criteria for detecting diabetes or prediabetes in asymptomatic adults. detecting diabetes or prediabetes in asymptomatic adults.2 In 2010, the American Diabetes Association (ADA) recommended the use of HbA1c (A1C) for the diagnosis of type 2 diabetes.2 This was based on the results of a test with a limit or cut-off point of ≥ 6.5% (48 mmol/mol).3 This limit was strongly related to retinopathy. The ADA has recently published standards for classification and diagnosis of diabetes, which broaden the range of its categorization to include prediabetes with A1C levels ranging from 5.7% to 6.4% (39–47 mmol/mol). This article examines the researches of scientists in different countries.