Association between serum uric acid and muscle strength according to glycemic status in older adults: NHANES 1999–2002

Hyperglycemia induces heightened oxidative stress, potentially leading to reduced muscle strength. Consequently, compounds with antioxidant properties could potentially offer protection against this decline. Uric acid (UA) is known for its antioxidant effects and has shown a positive association with muscle strength in older adults. However, whether this association extends to older adults with hyperglycemia remains unknown.

To assess the association between UA levels and muscle strength in older adults, stratified by glycosylated hemoglobin levels.

A cross-sectional study was conducted, involving 2380 individuals aged 50 to 85 years (1500 normoglycemic and 880 hyperglycemic), selected from a subsample of the National Health and Nutrition Examination Survey (NHANES) 1999–2002. Hyperglycemia was defined as glycosylated hemoglobin levels ≥ 5.7%. Muscle strength was assessed using a kinetic communicator isokinetic dynamometer. Serum UA levels were measured using a colorimetric method. Linear regression analyses were employed to examine the association of continuous UA values and tertiles of UA levels with muscle strength based on glycemic status, adjusting for potential confounding factors.

Tertiles of UA levels showed a positive association with peak force in individuals with hyperglycemia (p-trend = 0.013), but not in those with normoglycemia (p-trend = 0.077). Moreover, continuous UA values were positively associated with muscle strength in older adults with hyperglycemia (β = 5.2 (0.6; 9.8); p = 0.027), whereas no association was observed in those with normal glycemia (β = 2.4 (− 2.1; 6.9); p = 0.282).

Serum UA exhibits a positive association with muscle strength in older adults with hyperglycemia; however, this association is not observed in individuals with normal glucose levels. These results suggest that UA levels may play a crucial role in muscle strength, particularly in older adults experiencing heightened oxidative stress induced by hyperglycemia.