Uric acid, impaired fasting glucose and impaired glucose tolerance in youth with overweight and obesity

Background and aim: The relationships between uric acid (UA) and prediabetes is poorly
explored in youth. We investigated the association between UA, impaired fasting glucose (IFG),
impaired glucose tolerance (IGT), insulin resistance (IR) and low insulin sensitivity (IS) in youth
with overweight/obesity (OW/OB).
Methods: A cross-sectional study was performed in 2248 youths with OW/OB (age 5-17 years).
The sample was stratified in sex-specific quintiles (Q1 to Q5) of UA and the associations with
fasting (FG), 2-hour post-load glucose (2H-PG), IR and low IS were investigated. IR and low IS
were estimated by assessment model of insulin resistance (HOMA-IR) and whole-body IS index
(WBISI), respectively. IFG was defined as FG >=100<126 mg/dL, IGT as 2H-PG >=140<200 mg/dL,
IR as HOMA-IR >=75th percentile and low IS as WBISI <=25th percentile by sex.
Results: Age, body mass index z-score, 2H-PG, HOMA-IR and WBISI, increased across sexquintiles
of UA while FG did not. The prevalence of IFG and IR were significantly increased in Q5
vs Q1 (reference quartile, P <0.025). The prevalence of IGT increased from Q3 to Q5 vs Q1 (P
<0.025-0.0001) and that of low IS from Q2 to Q5 vs Q1 (P <0.005-0.0001).
Conclusions: In youth with OW/OB, rates of IGT and low IS increased progressively across
quintiles of UA. On the contrary, IFG and IR were associated only with the highest quintile of UA.
Our data suggest that UA is a biomarker of impaired glucose metabolism prevalently in postchallenge
condition rather than in fasting state.