title: Antioxidants and self-reported history of kidney stones: the National Health and Nutrition Examination Survey.
abstract: OBJECTIVE
  Animal studies have demonstrated the likely role of oxidative tissue damage in the pathophysiology of stone disease; however, the effect of antioxidants on stone formation in the human population is unknown. We evaluated the association between serum antioxidant levels and the self-reported prevalence of kidney stones in a large cross-sectional population in a retrospective cohort study.
  
  
  METHODS
  Serum levels of antioxidants among adult participants in the National Health and Nutrition Examination Survey (NHANES III) 1988-1994 were compared between those with and without a self-reported history of kidney stones, adjusting for covariates of age, sex, body mass index (BMI), race/ethnicity, diabetes, and hypertension.
  
  
  RESULTS
  The prevalence of kidney stones was 5.25% (95% confidence interval: 4.60%, 5.90%). The prevalence of kidney stones was higher in males, white/non-Hispanics, diabetics, and those with hypertension. The prevalence of kidney stones increased with BMI. After adjusting for covariates, mean levels of alpha-carotene, beta-carotene, and beta-cryptoxanthin were significantly lower in those with kidney stones (-9.36%, -10.79%, and -8.48%, respectively). When analyzed by quartile, higher serum levels of beta-carotene and beta-cryptoxanthin,, trended toward a decreasing prevalence of stones (P=0.007 and P=0.03, respectively), indicating that the highest levels of these antioxidants may protect against the formation of kidney stones.
  
  
  CONCLUSIONS
  Lower levels of alpha-carotene, beta-carotene, and beta-cryptoxanthin are associated with a history of kidney stones and may indicate a role for these antioxidants in preventing stone formation.
authors.affiliation: Department of Urology, University of Iowa, Iowa City, Iowa 52242-1089, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Holoch
authors.forename: Chad R
authors.initials: CR
authors.lastname: Tracy
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D006801:Humans; D007669:Kidney Calculi / Q000453:epidemiology*; D009749:Nutrition Surveys; D016017:Odds Ratio; D057566:Self Report; D014481:United States / Q000453:epidemiology
chemical_list: D000975:Antioxidants