Association of serum uric acid level with muscle strength and cognitive function among Chinese aged 50-74 years

Abstract

Aim: Previous studies have shown that uric acid (UA) has strong anti-oxidant properties, and that high circulating levels of UA are prospectively associated with improved muscle function and cognitive performances in elderly Caucasians. We carried out a replication study in elderly Chinese using cross-sectional design.

Methods: Data from 2006 individuals aged 50-74 years who participated in a population-based cross-sectional survey in Qingdao, China, were analyzed. Hand grip strength was measured in kilograms by using an electronic dynamometer. The sit-to-stand (STS) test time was used to represent lower limb strength. The Mini-Mental State Examination (MMSE) was used to estimate the participants' cognitive function. Lifestyle, comorbidities and laboratory measures were considered as potential confounders. Multiple linear regression models and binary logistic regression were fitted to find the association of UA with strength measures and cognitive performances.

Results: Participants were grouped according to UA tertiles (<257.75 mmol/L, ≥ 257.75 and ≤ 359.00 mmol/L, >359.00 mmol/L). Hand grip strength significantly increased across UA tertiles (26.4 ± 8.5 kg; 30.1 ± 10.5 kg; 35.0 ± 11.4 kg; P<0.001), and prevalence of cognitive disorder declined across UA tertiles (7.9%, 4.9%, 3.1%; P=0.012). After adjusting for potential confounders, high UA level remained significantly associated with high grip strength (P=0.023) and decreased risk of cognitive disorder with an OR of 1.002 (95% CI 1.000-1.004; P=0.022). However, UA level was not significantly associated with STS time (P=0.780).

Conclusions: Our findings suggested that notwithstanding the associated increased risk of cardiovascular disease, UA might play a protective role in aging-associated decline in muscle strength and cognitive function.

Keywords: aging; anti-oxidants; cognitive function; hand grip strength; uric acid.