Serum Uric Acid is Independently Related to New-Onset Anemia in General Population: Results from the TCLSIH Cohort Study

Background: Serum uric acid (SUA) is a major antioxidant molecule in the human blood.  It provides a protective role in red blood cells (RBCs) and hemoglobin (Hb) by antioxidant defense.  However, studies directly assessing the association between SUA and anemia are rare.  This study aimed to prospectively investigate the association between SUA and incident anemia in a general adult population. Methods: A total of 23,004 participants with no history of anemia were enrolled in the cohort study.  SUA levels were measured by enzymatic colorimetric test.  Hb was determined by sodium lauryl sulfate methemoglobin methods and anemia was defined as fasting blood Hb below 130g/L for men and 120 g/L for women. Cox proportional hazards regression models were used to examine the association of SUA with incident anemia.  Results: A total of 1,268 first incident cases of anemia occurred during 87,835 person-years of follow-up (median follow-up of 4.2 years). The fully adjusted hazards ratios (95% confidence interval) of anemia across increasing quartiles of SUA were 1.00(reference), 0.80(0.49, 1.30), 0.71(0.42, 1.22) and 0.83(0.49, 1.43) ( P for trend=0.92) in men, 1.00(reference), 0.84(0.71, 0.99), 0.82(0.69, 0.97) and 0.72(0.60, 0.86) ( P for trend=0.0003) in women, respectively. When comparing hyperuricemia to the lowest SUA level, the fully adjusted HRs (95% CIs) were 0.87 (0.49, 1.54) ( P value=0.64) in men and 0.77 (0.57, 1.03) ( P value=0.07) in women. Conclusions: Higher SUA is significantly associated with lower risk of incident anemia in women with normouricemia. This suggests that SUA may be a protective factor in the early detection of individuals at risk of anemia. Funding: This study was supported by grants from the National Natural Science Foundation of China (No. 91746205 and 81941024). Declaration of Interest: The authors declared they have no potential conflicts of interest. Ethical Approval: The study protocol complied with the Declaration of Helsinki and was approved by the institutional review board of the Tianjin Medical University.