Interactive effect of serum uric acid and handgrip strength on all-cause mortality among Japanese community-dwelling people.

Background: Uric acid is both a pro-oxidant and an antioxidant. This study examined whether serum uric acid (SUA) is associated with all-cause mortality and cardiovascular biomarkers in members of the general population who had varying levels of handgrip strength (HGS). Methods: The analysis is based on 1736 participants, of whom 785 were male (69 ± 11 years old) and 951 were female (69 ± 9 years old). We obtained adjusted relative risk estimates for all-cause mortality from the Japanese Basic Resident Registry and used a Cox proportional hazards model (adjusted for possible confounders) to determine the hazard ratios (HR) and 95% confidence intervals (CI). Results: The results indicated a significant interaction between the effects of SUA levels and HGS on all-cause mortality risk. Among participants with low HGS (<30.0 kg in males, <20.0 kg in females), low SUA levels (<3.5 mg/dL in males, <3.0 mg/dL in females; HR: 2.40; 95% CI: 1.07-5.40) and high SUA levels (≥8.0 mg/dL in males, ≥7.0 mg/dL in females; HR: 3.05; 95% CI: 1.41-6.59) were associated with a significantly higher HR for all-cause mortality than medium SUA levels (3.5-7.9 mg/dL in males, 3.0-6.9 mg/dL in females). Among participants with high HGS (≥30.0 kg in males; ≥20.0 kg in females), there was no difference between the HR for all-cause mortality between the three SUA-category groups. Conclusions: The association between SUA and the risk of all-cause mortality was U-shaped for this population of community-dwelling adults. This was primarily true for those with low HGS.