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

Osteoporosis is associated with decreased antioxidant defenses and serum uric acid (UA) as an antioxidant may exert a protective effect on bone mass. This study aimed to determine the association between serum UA and bone mineral density (BMD) in the elderly population. 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). 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 osteoporosis 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). These findings indicate a negative association between serum UA and osteoporosis in the elderly population aged ≥ 60 years.