title: Vitamin D and prevention of colorectal adenoma: a meta-analysis.
abstract: BACKGROUND
  Vitamin D status is associated inversely with risk of colorectal cancer, but the association with adenoma risk is less clear. This meta-analysis examined the overall relationship between circulating (plasma or serum) 25-hydroxyvitamin D [25(OH)D], vitamin D intake (dietary, supplemental, or total), and colorectal adenoma incidence in published studies.
  
  
  METHODS
  A meta-analysis composed of 17 epidemiologic studies [1 cross-sectional, 9 case-control, and 7 cohort or nested case-control studies; 7 on 25(OH)D and 12 on vitamin D intake] published before December 2007 was done to examine the association between circulating 25(OH)D, vitamin D intake, and colorectal adenomas. Summary Peto odds ratios (OR) were computed for overall and stratified analyses.
  
  
  RESULTS
  Circulating 25(OH)D was inversely associated with risk of colorectal adenomas: the OR was 0.70 [95% confidence interval (95% CI), 0.56-0.87] for high versus low circulating 25(OH)D. The highest quintile of vitamin D intake was associated with an 11% marginally decreased risk of colorectal adenomas compared with low vitamin D intake (OR, 0.89; 95% CI, 0.78-1.02). For recurrent adenomas, there was a decreased risk of 12% (95% CI, 0.72-1.07) among individuals with high versus low vitamin D intake. The inverse associations appeared stronger for advanced adenoma [OR, 0.64; 95% CI, 0.45-0.90 for serum 25(OH)D and OR, 0.77; 95% CI, 0.63-0.95 for vitamin D intake], but the number of studies was small.
  
  
  CONCLUSIONS
  Both circulating 25(OH)D and vitamin D intake were inversely associated with colorectal adenoma incidence and recurrent adenomas. These results further support a role of vitamin D in prevention of colorectal adenoma incidence and recurrence.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: Melissa Y
authors.initials: MY
authors.lastname: Wei
authors.forename: Cedric F
authors.initials: CF
authors.lastname: Garland
authors.forename: Edward D
authors.initials: ED
authors.lastname: Gorham
authors.forename: Sharif B
authors.initials: SB
authors.lastname: Mohr
authors.forename: Edward
authors.initials: E
authors.lastname: Giovannucci
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000517:prevention & control*; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D009364:Neoplasm Recurrence, Local; D012306:Risk; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D