Ware M, Carreau A, Garcia-Reyes Y, Rahat H, Diniz-Behn C, Cree-Green MAbstract
Background: Adolescent girls can present with postprandial, episodic symptoms of dizziness and excess sweating, which are often clinically disregarded. These symptoms can be associated with idiopathic reactive hypoglycemia (RH), reproduced with a glucose challenge, and may relate to increased risk of insulin resistance and type 2 diabetes (T2D).
Hypothesis: Following an oral sugar tolerance test (OSTT), adolescent girls with obesity have a high prevalence of RH, which relates to increased early insulin secretion.
Methods: Secondary analysis of 112 adolescent girls with obesity (age 12-21 yrs; BMI≥90th percentile). Participants completed a 4-hr OSTT (75 g glucose, 25 g fructose) and were stratified by glucose nadir after 120 min: ≤60 mg/dL as RH, ≥80 mg/dL as normoglycemic (NG), and 61-79 mg/dL as indeterminate. Area under the curve (AUC) of glucose, insulin, glucagon, and C-peptide and measures of insulin sensitivity and β-cell function including oral minimal model, insulinogenic index, and oral disposition index were calculated. Demographic, physical, and metabolic characteristics between RH and NG were compared with Student’s t-tests or Mann-Whitney U tests. OSTT curves were compared with repeated measures ANOVA.
Results: In this cohort, 12% of girls had RH (n=13) and 36% had NG (n=40). Groups were similar for age, race, ethnicity, and BMI. Glucose concentrations were lower in RH than NG when fasting (p=0.033), at 210 mins (p=0.001), and 240 mins (p<0.001). In RH, glucose nadir occurred at a median time of 210 mins postprandial. RH had higher glucagon AUC for 90-240 mins of the OSTT (p=0.035) and lower insulin at 240 mins (p=0.007) confirming a counterregulatory response. Insulin AUC (p=0.074) and C-peptide AUC (p=0.054) for 0-120 min trended to be higher. Groups had similar hemoglobin a1c, family history of T2D, insulin sensitivity, and β-cell function.
Conclusions: RH was relatively common in this cohort of adolescent girls with obesity and occurred at 3-4 hrs. Early higher insulin secretion preceded the counterregulatory RH responses but was not related to insulin sensitivity. Future studies should aim to further understand the long-term effects of RH during adolescence and its significance in predicting future hyperglycemia.