The interplay between uric acid and antioxidants in relation to physical function in the elderly

Objectives: To investigate the relationship between uric acid and antioxidant concentrations and whether antioxidants modulate the impact of uric acid on physical function. Methods: 966 community-dwelling older persons included in the baseline assessment of the InCHIANTI Study. Uric acid, carotenoid, tocopherol, and selenium concentrations were assayed. Physical function was measured using the Short Physical Performance Battery (SPPB) and IADLs. Potential confounders were assessed using standardized methods. Results: Total carotenoids (p = .008), in particular α-carotene (p = .02), lutein (p < .001), zeaxanthin (p < .001), lycopene (p = .07), cryptoxanthin (p = .29), and selenium (p = .04) were inversely associated with UA. Total tocopherols (p = .06) and α-tocopherol (p = .10) had a positive trend across uric acid. SPPB (p = .01) and IADL disability (p = .002) were nonlinearly distributed across the uric acid quintiles. Participants within the middle uric acid quintile (4.8-5.3mg/ dl) were less disabled in IADLs and had better SPPB scores than those in the extreme uric acid quintiles. There was a significant interaction between uric acid and selenium in the model predicting SPPB score (p = .02). Conclusions. Uric acid is inversely associated with carotenoids and selenium. Participants with intermediate uric acid levels had a higher prevalence of good physical functions, higher SPPB scores, and lower IADL disability. In conclusion, older subjects with intermediate uric acid levels may have an optimum balance between proinflammatory and antioxidant compounds that may contribute to better physical performance.