Serum uric acid is positively associated with muscle strength in older men and women: Findings from NHANES 1999-2002

Abstract

Background: One of the causes of strength loss in older adults is the increased oxidative stress; thus, substances with antioxidants properties may have protective effects on muscle strength. Uric acid (UA) is an important antioxidant and it seems to be positively associated with muscle strength in older adults; however, the current evidence is still limited.

Aim: To investigate whether serum UA is associated with muscle strength in older men and women.

Methods: A cross-sectional study was performed evaluating older adults aged from 50 to 85 years from National Health and Nutrition Examination Survey (NHANES) 1999-2000 and 2001-2002. A total of 2361 individuals (1256 men and 1105 women) were evaluated. The peak isokinetic knee extensor strength was assessed by kinetic communicator isokinetic dynamometer; while UA levels were measured by colorimetric method. Linear regression analyses were performed to estimate the coefficients and 95% confidence intervals for muscle strength by quintiles of UA levels, adjusted for potential confounders.

Results: In the unadjusted analyses, serum UA was positively associated with peak force in men and total sample, but not in women. However, after adjustments for confounders, UA levels were positively associated with peak force in total sample (p-trend = 0.007), men (p-trend = 0.044) and women (p-trend = 0.016).

Conclusion: Serum UA is positively associated with muscle strength in older men and women. These results suggest that UA levels seem to be a protective factor for muscle strength in older adults independent of the sex.

Keywords: Aging; Muscle strength; Oxidative stress; Peak force; Uric acid.