J Am Soc Nephrol. 2009 Dec;20(12):2631-9. Epub 2009 Oct 29.
Melamed ML, Astor B, Michos ED, Hostetter TH, Powe NR, Muntner P.
Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA. mmelamed at aecom.yu.edu
Black individuals have lower 25-hydroxyvitamin D 25(OH)D levels and experience a disproportionate burden of ESRD compared with white individuals. Animal studies suggest that vitamin D has renoprotective effects. We evaluated the contribution of low 25(OH)D levels on incidence of ESRD using data from the Third National Health and Nutrition Examination Survey-linked Medicare claims files (n = 13,328). We included baseline (1988 through 1994) measurements of 25(OH)D and assessed the incidence of ESRD through July 31, 2001.
Overall, 34% of non-Hispanic black individuals had 25(OH)D levels <15 ng/ml compared with 5% of non-Hispanic white individuals (P < 0.001).
During a median of 9.1 yr, 65 participants developed ESRD.
After adjustment for demographic, socioeconomic, and clinical and laboratory factors (including diabetes, hypertension, estimated GFR, and albuminuria), participants with 25(OH)D levels <15 ng/ml had a 2.6-fold greater incidence of ESRD than those with levels > or =15 ng/ml (incidence rate ratio 2.64; 95% confidence interval CI 1.00 to 7.05; P = 0.05).
After adjustment for clinical covariates but not 25(OH)D levels, non-Hispanic black individuals had a 2.83-fold (95% CI 1.03 to 7.77) higher risk for developing ESRD compared with non-Hispanic white individuals.
Additional adjustment for 25(OH)D levels reduced the risk by 58% (incidence rate ratio 1.77; 95% CI 0.38 to 8.21).
In summary, low 25(OH)D levels associate with development of ESRD even after adjustment for multiple risk factors.
Low 25(OH)D levels may account for a substantial proportion of the increased risk for ESRD experienced by black individuals.