Implications of Rising Prediabetes Prevalence

G iven the burden of type 2 diabetesand its complications, much atten-tion has been given to prevention, beginning with identifying at-risk indi-viduals prior to diagnosis. This has led to the designation of “prediabetes, ” which is an intermediate form of dysglycemia on a spectrum ranging from normal to overt diabetes. The American Diabetes Associ-ation defines prediabetes as a fasting glu-cose of 100 to,126 mg/dL (impaired fasting glucose [IFG]), a 2-h plasma glu-cose of 140 to,200 mg/dL after a 75-g oral glucose tolerance test (impaired glu-cose tolerance [IGT]), or HbA1c 5.7 % (39 mmol/mol) to,6.5 % (48mmol/mol) (1). Fasting glucose$100 mg/dL portends an increased risk of diabetes (2,3), cardiovas-cular disease (CVD) in women (2), and mortality (4). HbA1c levels 5.5 % (37 mmol/mol) to,6.5 % (48 mmol/mol) are associated with an increased risk of diabetes and CVD compared with lev-els,5.5 % (37 mmol/mol) even after ad-justment for fasting glucose and key CVD risk factors (3). Because of these associ-ated risks, surveillance of prediabetes al-lows better prediction of diabetes trends and of the resources that will be required to treat rising diabetes. In the current issue of Diabetes Care, Bullard et al. (5) review secular trends in U.S. prediabetes prevalence using Na-tional Health and Nutrition Examination Surveys (NHANES) data from 1999 to 2010. Prediabetes was defined as HbA1c 5.7 % (39 mmol/mol) to,6.5 % (48 mmol/mol) or fasting glucose 100 to, 126 mg/dL; oral glucose tolerance tests (OGTTs) were not used. Participants completed a household interview fol-lowed by physical examination at mobile centers. A total of 19,182 participants ages $12 years were included in the analysis. The authors report an increase in over-all age-adjusted prediabetes prevalence from 27.4 % in 1999–2002 to 34.1 % in 2007–2010. Notably, the increase was solely the result of more individuals ful-filling the HbA1c criterion, which was met by 9.5 % in 1999–2002 and 17.8 % in 2007–2010, whereas the prevalence of IFG remained essentially unchanged (23.8– 25.9%). The findings were similar after adjustment for important covariates in-cluding BMI. Analyses of ethnic sub-groups revealed an increasing prevalence of prediabetes HbA1c levels among non