Inverted U-shaped associations between serum uric acid and fasting - plasma glucose level in non-diabetic, pre-diabetic, and diabetic adults: A population-based study in China

Objective This study was designed to examine the correlation between serum uric acid (SUA) and fasting plasma glucose (FPG) levels across non-diabetic, pre-diabetic, and diabetic adults from Northwest China.Materials and Methods This study utilized data from a cross-sectional survey conducted in Ningxia Hui Autonomous Region, which investigated the prevalence and risk factors of cardiovascular disease. All subjects underwent tests for SUA and FPG levels. Generalized additive models and two-piecewise linear regression models were applied to explore the relationships between SUA and FPG level. The triglyceride-glucose (TyG) index was examined as a measure of insulin resistance, with an analysis of its mediating effects on the association between SUA and FPG level.Results A total of 10,217 individuals aged 18 and over were included. Generalized additive models verified the inverted U-shaped association between SUA and FPG levels, and the inflection points of FPG levels in the curves were 6.5 mmol/L in males and 8.8 mmol/L in females. The TyG index is an intermediate variable in the relationship between SUA levels and elevated FPG levels, with mediating effects of 12.82% (P < 0.001) for males and 34.02% (P < 0.001) for females.Conclusions An inverted U-shaped association between FPG and SUA levels was observed in both genders. The threshold of FPG level was lower in males than in females. The relationship between these variables seems to be partially mediated by serum insulin levels.