The role of serum uric acid as an antioxidant protecting against cancer: prospective study in more than 28 000 older Austrian women.

BACKGROUND: It has been hypothesized that serum uric acid (SUA), via its antioxidant properties may protect against carcinogenesis. However, few epidemiological investigations have addressed this association and previous findings are inconsistent. PATIENTS AND METHODS: We prospectively investigated the relation of SUA levels to subsequent cancer mortality in a large cohort of 28613 elderly Austrian women with a median follow-up of 15.2 years. Adjusted Cox proportional hazards models were calculated to evaluate SUA as an independently related factor to fatal cancer events. RESULTS: High SUA (>5.41 mg/dL) was independently associated with increased risk of total cancer mortality (p<0.0001); the adjusted hazard ratio for the highest versus lowest quartile of SUA was 1.27 (1.08-1.48). SUA levels were further positively related to deaths from malignant neoplasms of breast and female genital organs (P = 0.02) and nervous system and unspecified sites (P = 0.02). We found no evidence for an inverse relationship between SUA levels and risk of total or site-specific cancer mortality. CONCLUSION: Our results are contrary to the proposed antioxidant and protective effect of SUA against cancer and rather suggest high SUA concentrations to be associated with outcome possibly reflecting more serious prognostic indication.