title: 25-Hydroxyvitamin D levels and albuminuria in the Third National Health and Nutrition Examination Survey (NHANES III).
abstract: BACKGROUND
  Albuminuria is a risk factor for chronic kidney disease progression, end-stage renal disease, cardiovascular events, and mortality. Animal studies suggested that vitamin D insufficiency may contribute to the pathogenesis of albuminuria.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  15,068 adults participating in the Third National Health and Nutrition Examination Survey.
  
  
  METHODS
  Serum 25-hydroxyvitamin D concentration, examined in quartiles.
  
  
  METHODS
  Albuminuria, defined using established sex-specific cutoff values for urine albumin-creatinine ratio (25 to 2,999 mg/g for women, 17 to 2,999 mg/g for men).
  
  
  RESULTS
  A stepwise increase in the prevalence of albuminuria was observed with decreasing quartiles of vitamin D concentration: 8.9%, 11.5%, 13.7%, and 15.8% (P < 0.001). Adjusting for age, sex, race/ethnicity, region and season of measurement, smoking status, body mass index, and estimated glomerular filtration rate, relative risks for albuminuria by decreasing quartile of vitamin D concentration were 1.00 (reference group), 1.14 (95% confidence interval, 0.95 to 1.37), 1.22 (95% confidence interval, 1.03 to 1.45), and 1.37 (95% confidence interval, 1.10 to 1.71; P = 0.006). Additionally adjusting for blood pressure and diabetes mellitus, these risks were somewhat attenuated and retained statistical significance.
  
  
  CONCLUSIONS
  The cross-sectional design of this study does not allow demonstration of temporal or causal relationships between vitamin D and albuminuria.
  
  
  CONCLUSIONS
  Additional studies are needed to clarify the relationship of vitamin D with albuminuria and determine whether vitamin D therapy prevents or improves markers of kidney and cardiovascular disease.
authors.affiliation: Division of Nephrology, University of Washington, Seattle, WA 98117, USA. deboer@u.washington.edu <deboer@u.washington.edu>
authors.forename: Ian H
authors.initials: IH
authors.lastname: de Boer
authors.forename: George N
authors.initials: GN
authors.lastname: Ioannou
authors.forename: Bryan
authors.initials: B
authors.lastname: Kestenbaum
authors.forename: John D
authors.initials: JD
authors.lastname: Brunzell
authors.forename: Noel S
authors.initials: NS
authors.lastname: Weiss
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000419:Albuminuria / Q000150:complications / Q000453:epidemiology* / Q000208:ethnology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D015995:Prevalence; D012016:Reference Values; D012621:Seasons; D014481:United States / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D