Sex-specific distribution of the uric acid-to-HDL cholesterol ratio and its association with arterial stiffness in a Japanese health check-up population: a cross-sectional analysis

Background The uric acid to HDL-cholesterol ratio (UHR) is a composite marker of metabolic and inflammatory imbalance. Although a previous study in a Japanese health check-up population reported a positive and nonlinear association between UHR and brachial-ankle pulse wave velocity (baPWV), the interpretation of sex-specific heterogeneity remains unclear. Therefore, the association between UHR and baPWV was re-examined, with particular attention to the sex-specific distribution of UHR and the robustness of sex-stratified findings. Methods This cross-sectional analysis was based on 912 participants. UHR was derived from the ratio of serum uric acid to HDL-cholesterol and was modeled as both a continuous measure and a quartile-based variable. Multivariable linear regression was used to assess its association with baPWV. To further characterize the shape of the association, restricted cubic spline fitting and piecewise linear regression were performed. Stratified analyses were also conducted across subgroups defined by age, sex, estimated glomerular filtration rate, drinking behavior, smoking, and physical activity, with additional attention to the distribution of UHR in men and women and menopausal status among women. Results baPWV increased across UHR quartiles. After multivariable adjustment, UHR remained positively associated with baPWV, and higher UHR quartiles showed significantly higher baPWV than the lowest quartile, with a significant trend. Restricted cubic spline analysis showed a nonlinear association between UHR and baPWV (P for overall of 0.001; P for non-linearity of 0.002). The inflection point was identified at a UHR value of 6.261, with a significant positive association below this point but no statistically significant association above it. Subgroup analyses suggested possible heterogeneity by age and sex. The association was statistically clear among participants younger than 65 years and among women, whereas the estimate in older participants was imprecise and no significant association was observed in men. Conclusion UHR was positively associated with baPWV, with evidence of a nonlinear pattern and an inflection point at a UHR value of 6.261. The sex-specific findings should be interpreted cautiously because UHR values differed markedly between men and women and women were sparsely represented in the higher UHR range. UHR may help identify medication-free individuals with higher baPWV, but prospective studies are needed to confirm its incremental clinical value.