Independent association of serum retinol and β-carotene levels with hyperuricemia: A national population study.

Objective: Uses of synthetic vitamin A derivatives (e.g., isotretinoin used for severe acne) and high doses of preformed vitamin A have been implicated in the pathogenesis of hyperuricemia and gout, whereas a trial reported that β-carotene may lower serum uric acid (UA) levels. We evaluated the potential population impact of these factors on serum UA in a nationally representative sample of US adults.

Methods: Using data from 14,349 participants ages ≥20 years in the Third National Health and Nutrition Examination Survey (1988-1994), we examined the relationship between serum retinol, β-carotene, and UA levels using weighted linear regression. Additionally, we examined the relationship with hyperuricemia using weighted logistic regression.

Results: Serum UA levels increased linearly with increasing serum retinol levels, whereas serum UA levels decreased with increasing serum β-carotene levels. After adjusting for age, sex, dietary factors, and other potential confounders, the serum UA level differences from the bottom (referent) to the top quintiles of serum retinol levels were 0, 0.16, 0.32, 0.43, and 0.71 mg/dl (P for trend <0.001), and for β-carotene were 0, -0.15, -0.29, -0.27, and -0.40 mg/dl (P for trend <0.001), respectively. Similarly, the multivariate odds ratios of hyperuricemia from the bottom (referent) to top quintiles of serum retinol levels were 1.00, 1.30, 1.83, 2.09, and 3.22 (P for trend <0.001) and for β-carotene were 1.00, 0.85, 0.68, 0.73, and 0.54 (P for trend <0.001), respectively. The graded associations persisted across subgroups according to cross-classification by both serum retinol and β-carotene levels.

Conclusion: These nationally representative data raise concerns that vitamin A supplementation and food fortification may contribute to the high frequency of hyperuricemia in the US population, whereas β-carotene intake may be beneficial against hyperuricemia. The use of β-carotene as a novel preventive treatment for gout deserves further investigation.