Despite extensive studies conducted on the relationship between serum uric acid (UA) and bone mineral density (BMD), their association remains controversial. In this study, we investigated whether UA levels are independently associated with BMD in Chinese and American populations to elucidate their association. Herein, the data of 12,344 individuals (age >
20 years) from the National Health and Nutrition Examination Survey (2005-2018) and those of 768 individuals from the inpatient medical records and physical examination center systems of the Tertiary Class A Hospital (2021-2023) from China were included. The association between UA and BMD was analyzed by employing multivariate regression models with covariate adjustments. In addition, population description, stratified analysis, single-factor analysis, smooth-curve fitting, and threshold and saturation effect analyses were performed. After covariate adjustments, UA exhibited an association with BMD of the femur (β = 0.008, 95% confidence interval [CI] 0.001-0.015, P = 0.02), femoral neck (β = 0.011, 95% CI 0.004-0.018, P = 0.002), and lumbar spine (β = 0.014, 95% CI 0.06-0.022, P <
0.001) in American subjects. Similarly, UA exhibited association with BMD of the femur (β = 0.079, 95% CI 0.042-0.117, P <
0.001), femoral neck (β = 0.171, 95% CI 0.121-0.22, P <
0.001), and lumbar spine (β = 0.052, 95% CI 0.007-0.097, P = 0.024) in Chinese subjects. Notably, the relationship between UA levels and BMD was nonlinear. The saturated utility values for determining the UA level with BMD of the femur and femoral neck using a two-stage linear regression model were 429.9 and 468 μmol/L, respectively, in the Chinese population. In the American population, the saturated utility values of UA level with BMD of the femur, femoral neck, and lumbar spine were 410.4, 410.4, and 452 μmol/L, respectively. Altogether, the present findings suggested a positive association between the UA levels and overall BMD in adults, implying that maintaining saturated UA levels can facilitate osteoporosis prevention.China Clinical Trials Registry: MR-51-23-051741. https://www.medicalresearch.org.cn/search/research/researchViewid=c0e5f868-eca9-4c68-af58-d73460c34028 .