Using Glycosylated Hemoglobin to Define the Metabolic Syndrome in United States Adults

OBJECTIVE To compare the use of GHb and fasting plasma glucose (FPG) to define the metabolic syndrome (MetS). RESEARCH DESIGN AND METHODS Data from the U.S. National Health and Nutrition Examination Survey 1999-2006 were used. MetS was defined using the consensus criteria in 2009. Raised blood glucose was defined as either FPG >or=100 mg/dl (5.6 mmol/l) or GHb >or=5.7%. RESULTS In 2003-2006, there was 91.3% agreement between GHb and FPG when either was used to define MetS. The agreement was good irrespective of age, sex, race/ethnicity, BMI, and diabetes status (>or=87.4%). Similar results were found in 1999-2002. Among subjects without diabetes, only the use of GHb alone, but not FPG, resulted in significant association with cardiovascular diseases (odds ratio 1.45, P = 0.005). CONCLUSIONS Using GHb instead of FPG to define MetS is feasible. It also identifies individuals with increased cardiovascular risk.