title: Serum 25-hydroxyvitamin D and prevention of breast cancer: pooled analysis.
abstract: BACKGROUND
  Low serum levels of 25-hydroxyvitamin D [25(OH)D] have been associated with a high risk of breast cancer. Since publication of the most current meta-analysis of 25(OH)D and breast cancer risk, two new nested case-control studies have emerged.
  
  
  METHODS
  A PubMed search for all case-control studies on risk of breast cancer by 25(OH)D concentration identified 11 eligible studies. Data from all 11 studies were combined in order to calculate the pooled odds ratio of the highest vs. lowest quantile of 25(OH)D across all studies.
  
  
  RESULTS
  The overall Peto odds ratio summarizing the estimated risk in the highest compared to the lowest quantile across all 11 studies was 0.61 (95% confidence interval 0.47, 0.80).
  
  
  CONCLUSIONS
  This study supports the hypothesis that higher serum 25(OH)D levels reduce the risk of breast cancer. According to the review of observational studies, a serum 25(OH)D level of 47 ng/ml was associated with a 50% lower risk of breast cancer.
authors.affiliation: Department of Family and Preventive Medicine, University of California San Diego, 9500 Gilman Drive 0620, La Jolla, CA 92093-0620, USA. sbmohr75@gmail.com
authors.forename: Sharif B
authors.initials: SB
authors.lastname: Mohr
authors.forename: Edward D
authors.initials: ED
authors.lastname: Gorham
authors.forename: John E
authors.initials: JE
authors.lastname: Alcaraz
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kane
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Macera
authors.forename: J Kellogg
authors.initials: JK
authors.lastname: Parsons
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Wingard
authors.forename: Cedric F
authors.initials: CF
authors.lastname: Garland
mesh_terms: D001943:Breast Neoplasms / Q000097:blood / Q000517:prevention & control*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D