Non-linear associations between UHR and bone mineral density in US adults: NHANES 2017-2018

Bone mineral density (BMD) is a key indicator of bone health, particularly in older populations, where lower BMD is linked to increased risk of osteoporosis and fractures. Metabolic factors like serum uric acid (UA) and high-density lipoprotein cholesterol (HDL-C) have emerged as possible determinants of bone health. The uric acid to HDL cholesterol ratio (UHR) may offer a new perspective on these metabolic influences. This study explores the association between UHR and femoral neck BMD, with a focus on non-linear relationships and subgroup variations by body mass index (BMI), age, and sex.

The study used data from 2178 participants from the 2017-2018 National Health and Nutrition Examination Survey (NHANES). UHR was calculated as the ratio of serum UA to HDL-C. BMD measurements were obtained using dual-energy X-ray absorptiometry (DXA) at the femoral neck. A two-piecewise linear regression model was applied to examine the non-linear relationship between UHR and BMD. Stratified analyses were conducted by BMI, gender, and age groups.

A significant inflection point was found at UHR 19. Below this threshold, UHR was positively associated with femoral neck BMD (β = 0.0054, p = 0.013), while above the threshold, the association was negative but not statistically significant (β = - 0.0016, p = 0.478). Stratified analysis revealed that the relationship between UHR and BMD remained significant among Mexican Americans even after adjusting for covariates (β = 0.0145, p = 0.012).

This study identifies a non-linear association between UHR and femoral neck BMD, with a key inflection point at UHR 19. These findings suggest that UHR could be a useful biomarker for bone health, especially in populations with higher metabolic risks. Further longitudinal studies are necessary to establish causality and explore potential interventions targeting UHR to improve bone health.