Association between baseline and changes in serum uric acid and incident metabolic syndrome: a nation-wide cohort study and updated meta-analysis.

Background To prospectively examine the associations of baseline serum uric acid (SUA) and SUA changes with incident metabolic syndrome (MetS) and update the evidence through a meta-analysis. Methods Our analyses were based on the China Health and Retirement Longitudinal Study from 2011-2012 to 2015-2016. The exposures were baseline SUA and SUA changes, and the outcome was incident MetS assessed in 2015-2016. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). A meta-analysis was conducted to synthesize evidence from all cohort studies on the same topic. Results Of 3779 participants (47.2% men; mean age: 59.5 years) without MetS, 452 participants developed MetS after a follow-up of 4 years. Compared to the lowest quartiles, the adjusted ORs (95% CIs) for MetS were 1.08 (0.77-1.50), 1.32 (0.95-1.82), and 1.55 (1.12-2.16) for three higher quartiles of baseline SUA, and 1.23 (0.89-1.71), 1.39 (1.00-1.93), and 1.89 (1.38-2.58) for three higher quartiles of SUA changes. Each increment of 1 mg/dL of baseline SUA level was associated with 19% higher odds of MetS (adjusted OR 1.19; 95% CI 1.07-1.33). In the meta-analysis of 24 cohort studies among 140,913 participants, the pooled relative risk (95% CI) was 1.32 (1.25-1.40) for the highest versus lowest SUA category, and 1.15 (1.09-1.21) for each 1 mg/dL increase in the SUA level. Conclusions Both baseline SUA and longitudinal SUA changes were positively associated with risk of MetS among middle-aged and elderly Chinese, which was supported by findings from a comprehensive meta-analysis across multiple populations. SUA levels might need to be monitored closely for subsequent risk of MetS in clinical practice.