Association between being African-American, serum urate levels and the risk of developing hyperuricemia: findings from the Coronary Artery Risk Development in Young Adults cohort
1 Birmingham VA Medical Center 700 South 19th Street, Birmingham, AL 35233, USA
2 Divisions of Rheumatology 172 Shelby Interdisciplinary Biomedical Research Building, 1825 University Boulevard, Birmingham, AL 35294-2182, USA
3 Division of Epidemiology and Community Health, School of Public Health, University of Minnesota 1300 South Second Street, Suite 300, Minneapolis, MN 55454, USA
4 Department of Nutrition, University of Oslo, P.O.Box 1046 Blindern, N-0316 Oslo, Norway
5 Division of Preventive Medicine, Department of Medicine, 1530 3rd Avenue South, Medical Towers, Birmingham, AL 35294-4410, USA
6 Section of Rheumatology and Immunology, The University of Nebraska Medical Center, 986270 Nebraska Medical Center, Omaha, NE 68198, USA
Arthritis Research & Therapy 2012, 14:R4 doi:10.1186/ar3552Published: 6 January 2012
Findings that African-American race/ethnicity is associated with higher concentrations of serum urate have not been adjusted for possible confounding factors or have not explored this question as a primary outcome. We tested this hypothesis in a bi-racial cohort of younger African-American and white men and women.
Data from 5,049 participants at the Coronary Artery Risk Development in Young Adults (CARDIA) cohort baseline (1985 to1986) and follow-up for up to 20 years of individuals without hyperuricemia (defined as a serum urate of 6.8 mg/dL or more) at baseline were utilized. We determined associations between race, serum urate and the development of hyperuricemia in sex-specific cross-sectional and longitudinal analyses. Confounding factors examined included: age at enrollment, body mass index, development of hypertension, glomerular filtration rate, medication use, diet and alcohol intake and menopausal symptoms in women.
Referent to whites, African-American men and women had significantly lower concentrations of serum urate at baseline. African-American men had an essentially equal risk of developing incident hyperuricemia during follow-up compared with white men (multivariable adjusted HR = 1.12 (0.88 to1.40)). African-American women developed a significantly increased risk of hyperuricemia when compared to white women (HR = 2.31 (1.34 to 3.99)).
Young African-American men and women had lower concentrations of serum urate than whites. During longitudinal follow-up, African-American women had a significantly increased risk of developing hyperuricemia when compared with white women, a difference that was not observed in men. Differences in production of serum urate or a more rapid decline in fractional excretion of serum urate are potential, albeit still unproven, explanations for these findings in African-American women.