Abstract and Introduction
Abstract
Objective—To characterize middle-school students from the HEALTHY study with glycemic abnormalities, specifically high-risk hemoglobin A1c (A1C) (hrA1C; A1C = 5.7–6.4%) and impaired fasting glucose (IFG; fasting plasma glucose [FPG] = 100–125 mg/dL).
Research design and methods—History was collected by self-report, physical measurement was collected by trained study staff, and fasting blood was drawn by trained phlebotomists and analyzed centrally.
Results—At baseline, among 3,980 sixth graders, 128 (3.2%) had hrA1C and 635 (16.0%) had IFG. Compared with A1C <5.7%, hrA1C was associated with non-Hispanic black race/ethnicity, family history of diabetes, and higher measurements of BMI, waist circumference, and fasting insulin. Compared with FPG <100 mg/dL, IFG was associated with Hispanic ethnicity; increased BMI, waist circumference, and fasting insulin; higher frequency of high blood pressure; and higher mean triglycerides. Two years later, children with hrA1C persisted as hrA1C in 59.4%, and one child (0.8%) developed A1C ≥6.5%; children with IFG persisted with IFG in 46.9%, and seven children (1.1%) developed FPG ≥126 mg/dL. Those with hrA1C compared with IFG had a higher BMI in sixth grade, which persisted to eighth grade.
Conclusions—In the HEALTHY study cohort, hrA1C and IFG define different groups of youth with differentially increased diabetes risk markers. IFG is approximately fivefold more common, but hrA1C is more persistent over time. Optimal screening strategies for diabetes in youth remain unresolved.
Introduction
The HEALTHY study was conducted to determine if a middle-school–based intervention program could reduce risk factors for type 2 diabetes in a multiethnic cohort of students. The primary outcome for the study was a change in the percent of students with a BMI ≥85th percentile (combined prevalence of overweight and obesity adjusted for sex and age), which decreased by ~4% in both intervention and control schools (P = NS) from sixth to eighth grades; however, among the sample of students who were overweight or obese (≥85th percentile) in sixth grade (50% of the sample), intervention schools showed greater reductions in the prevalence of obesity (BMI ≥95th percentile) than control schools, suggesting that the intervention had an effect on obesity rather than on overweight.
Among other risk factors for type 2 diabetes, hemoglobin A1c (A1C) and fasting plasma glucose (FPG) were collected at baseline and the end of study. It has been suggested that A1C can identify adults with diabetes and prediabetes. There are few prospective data regarding glycemic risk markers in diverse populations of youth. HEALTHY data were used to determine the distribution, durability, and association of high-risk A1C (hrA1C) with other diabetes risk factors in comparison with impaired fasting glucose (IFG) to inform decision making regarding screening and prevention strategies in youth.