title: Vitamin D Intake and the Risk of Incident Kidney Stones.
abstract: Kidney stones are a common and painful condition. Longitudinal prospective studies on the association between the intake of vitamin D and the risk of incident kidney stones are lacking.
  
  
  
  We performed a prospective analysis of 193,551 participants in the Health Professionals Follow-up Study and Nurses' Health Study I and II. Participants were divided into categories of total (less than 100, 100 to 199, 200 to 399, 400 to 599, 600 to 999, 1,000 IU per day or greater) and supplemental (none, less than 400, 400 to 599, 600 to 999, 1,000 IU per day or greater) vitamin D intake. During a followup of 3,316,846 person-years there were 6,576 incident kidney stone events. Cox proportional hazards regression models were adjusted for age, body mass index, comorbidities, use of medications and intake of other nutrients.
  
  
  
  After multivariate adjustment there was no statistically significant association between vitamin D intake and risk of stones in the HPFS (HR for 1,000 or greater vs less than 100 IU per day 1.08, 95% CI 0.80, 1.47, p for trend = 0.92) and the NHS I (HR 0.99, 95% CI 0.73, 1.35, p for trend = 0.70), whereas there was a suggestion of a higher risk in the NHS II (HR 1.18, 95% CI 0.94, 1.48, p for trend = 0.02). Similar results were found for supplemental vitamin D intake.
  
  
  
  Vitamin D intake in typical amounts was not statistically associated with risk of kidney stone formation, although higher risk with higher doses than those studied here cannot be excluded.
authors.affiliation: Division of Nephrology, Fondazione Policlinico Universitario A. Gemelli, Catholic University of the Sacred Heart, Rome, Italy. Electronic address: pietromanuel.ferraro@unicatt.it.
authors.forename: Pietro Manuel
authors.initials: PM
authors.lastname: Ferraro
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; Division of Nephrology and Transplantation, Maine Medical Center, Portland, Maine.
authors.forename: Eric N
authors.initials: EN
authors.lastname: Taylor
authors.affiliation: Division of Nephrology, Fondazione Policlinico Universitario A. Gemelli, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gambaro
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Gary C
authors.initials: GC
authors.lastname: Curhan
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007669:Kidney Calculi / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014807:Vitamin D / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D014807:Vitamin D
keywords: cohort studies; diet; food and nutrition; urolithiasis; vitamin D