J-shaped association between the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and uric acid in Chinese adults

The non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) has emerged as a composite lipid indicator, but its association with serum uric acid (SUA) and hyperuricemia (HUA) remains insufficiently characterized, particularly in middle-aged and older Chinese adults. This cross-sectional study used baseline data from the China Health and Retirement Longitudinal Study (CHARLS). NHHR was calculated as (TC - HDL-C)/HDL-C. HUA was defined as SUA ≥ 7 mg/dL in men and ≥ 6 mg/dL in women. Survey-weighted multivariable linear and logistic regression models were used to examine associations of NHHR with SUA and HUA. Nonlinear relationships were explored using smooth curve fitting and two-piece linear regression models. Subgroup analyses and interaction tests were also conducted to investigate whether this relationship remains stable across different populations. A total of 11,132 participants aged ≥ 45 years were included. Higher NHHR was associated with higher SUA levels and greater odds of HUA in fully adjusted models. A nonlinear J-shaped association was observed between ln (NHHR) and SUA, with an inflection point at 1.49. Below this threshold, ln (NHHR) was inversely associated with SUA, whereas above it, the association became positive. A nonlinear pattern was also observed for HUA, although the association above the estimated threshold was not statistically significant. Subgroup analyses suggested potential effect modification by smoking and alcohol consumption; however, these findings were exploratory. In this cross-sectional analysis of middle-aged and older Chinese adults, NHHR was associated with SUA and HUA, and a J-shaped relationship was observed for SUA. These findings highlight a potential link between lipid imbalance and uric acid metabolism, which warrants further investigation in longitudinal and mechanistic studies.