Serum Uric Acid Status and Its Association with Bone Mineral Density in the Elderly People Aged 60 Years and More

Background: Osteoporosis is associated with decreased antioxidant defenses and serum uric acid (UA) as an antioxidant may exert a protective effect on bone mass. Objectives: This study aimed to determine the association between serum UA and bone mineral density (BMD) in the elderly pop- ulation. Methods: All participants of the Amirkola Health and Ageing Project aged ≥ 60 years entered the study. BMD in the femoral neck (FN-BMD) and lumbar spine (LS-BMD) was determined by dual energy X-ray absorptiometry and osteoporosis was defined as BMD T- score - 2.5 at either FN or LS. The patients were classified according to serum UA levels as 4; 4 - 4.99; 5 - 5.99; 6 - 6.99 and 7 mg/dL. In statistical analysis, the value of BMD as well as frequency of osteoporosis in each subgroup were compared with the control group (UA 4 mg/dL). Results: A total of 1080 patients were studied. By increasing serum UA from 4 mg/dL to 7 mg/dL the BMD at both measurement sites increased as well. The serum UA was associated with decreased risk of osteoporosis. In multivariate analysis, the odds of osteo- porosis in the subgroup with serum UA levels between 4 - 4.99 mg/dL was significantly lower than the control group (OR = 0.66, 95% CI, 0.44 - 0.99). Age and female sex were associated with increased odds of osteoporosis (OR = 1.08, 95% CI, 1.05 - 1.10 and OR = 10.62, 95% CI, 7.53 - 14.97 respectively). Conclusions: These findings indicate a negative association between serum UA and osteoporosis in the elderly population aged ≥ 60 years.