Background: Previous studies have identified biomarkers derived from glucose concentrations during a 2-h Oral Glucose Tolerance Test (OGTT) that differentiate type 2 diabetes risk phenotypes. Such markers include 1-h glucose concentrations (1hG), shape of the glucose response curve (GRC), and time to glucose peak (TGP). Lifestyle intervention is the first line approach to diabetes prevention, yet no studies have examined changes in OGTT-glucose phenotypes.
Methods: Latino adolescents with obesity (n=48, age 15.4±1.0, BMI% 98.2±1.4, Girls 56.3%) completed a 12-week lifestyle intervention that included physical activity (3 d/wk) and nutrition education (1 d/wk). At baseline and 12 weeks, youth completed a 2-h OGTT with glucose concentrations assessed at 0’, 30’, 60’, 90’, and 120’ to derive the 3 biomarkers used to classify low and high risk phenotypes. For 1hG, ≥155mg/dL served as the threshold that classified 1hG<155mg/dL (low risk) and 1hG≥155mg/dL (high risk) phenotypes. For GRC, Biphasic (low risk) phenotypes reached peak glucose levels before dropping ≥4.5mg/dL and increasing again ≥4.5mg/dL, whereas remaining youth were Monophasic (high risk). For TGP, phenotypes were distinguished by whether glucose peaked at 30’ (Early Peak, low risk) or ≥30’ (Late Peak, high risk). Changes in OGTT-glucose phenotypes were assessed by Chi-square test.
Results: At baseline, there was substantial heterogeneity in the prevalence of OGTT-glucose phenotypes with 38% 1hG≥155mg/dL, 81% Monophasic, and 58% Late Peak. In response to the intervention, the prevalence of Monophasic decreased to 14% (p=0.048), while the prevalence of 1hG≥155mg/dL decreased to 28% (p=0.054). The decrease in prevalence of Late Peak phenotypes was not significant (-29%, p=0.200).
Conclusion: Lifestyle intervention may improve OGTT-glucose phenotypes among high-risk youth populations. Whether changes in OGTT-glucose phenotypes are associated with changes in type 2 diabetes risk factors has yet to be established.
A. Pena: None. J. Kim: None. J. A. Reyes: None. K. B. Vander wyst: None. M. Olson: None. S. Ayers: None. A. Williams: None. G. Q. Shaibi: None.
National Institutes of Health (P20MD002316U54, MD002316R01, DK107579F31, DK125037)