Raised serum uric acid is associated with higher bone mineral density in a cross-sectional study of a healthy Indian population

Purpose: Oxidative stress has been implicated as a fundamental mechanism in the decline of bone mass. Reactive oxygen species are reported to suppress osteoblast generation and differentiation and enhance osteoclast development and activity. Increasing evidence suggests favorable effect of serum uric acid (UA) on bone metabolism due to its antioxidant properties. Therefore, we investigated the association between serum UA levels and bone mineral density (BMD) in healthy adult Indian subjects. Materials and methods: We reviewed the medical records of 524 subjects who had undergone preventive health check-ups in a tertiary care hospital that included UA and BMD measurements at femur neck, total femur, and lumbar spine. Subjects concomitantly taking drugs or having a medical condition that would affect the bone metabolism or UA levels were excluded. Results: The final analysis included 310 subjects (mean age: 47.2 +/- 12.2 years; females: 43.5%; males: 56.5%). Study population was categorized into two groups based on the group median value for UA (ie, 5.4 mg/dL). BMD was significantly higher at all skeletal sites in subjects with UA > 5.4 mg/dL compared to subjects with UA <= 5.4 mg/dL (p<0.001). On correlation analysis, UA was positively associated with BMD at all skeletal sites (r=0.211-0.277; p<0.05). The correlation remained significant after controlling for age (p<0.05) and lifestyle factors (smoking, alcohol use, physical activity, and diet; p<0.05) independently. UA significantly (p<0.001) accounted for 4.5%-7.7% of the variance in BMD (r(2)=0.045-0.077) in unadjusted model and 1.6%-3.2% of the variance (p<0.05) when adjusted for age and body mass index combined at lumbar spine and right femur neck, respectively. Conclusion: We conclude that raised UA levels are associated with higher BMD at all skeletal sites and UA may have a protective role in bone metabolism owing to its antioxidant effect.