title: 25-hydroxyvitamin D and breast cancer, colorectal cancer, and colorectal adenomas: case-control versus nested case-control studies.
abstract: BACKGROUND
  Existing literature includes concerns regarding reliability of case-control studies of breast cancer incidence with respect to 25-hydroxyvitamin D (25(OH)D) concentrations. For breast cancer, only case-control studies consistently find inverse correlations between 25(OH)D and breast cancer. However, for colorectal cancer, nested case-control studies find significant inverse correlations with respect to 25(OH)D concentrations at baseline for mean follow-up times of 7 years.
  
  
  METHODS
  This is a review of results currently existing in literature.
  
  
  RESULTS
  I provide evidence that 25(OH)D concentration values are only useful for short follow-up times for breast cancer since it develops rapidly. To support the robust nature of breast cancer case-control studies, I show that results from 11 studies from seven countries align in a robust power-law fit to the odds ratio versus mean 25(OH)D concentrations.
  
  
  CONCLUSIONS
  Case-control studies of breast cancer incidence rates provide reliable results.
authors: Sunlight, Nutrition, and Health Research Center, San Francisco, CA, U.S.A. wbgrant@infionline.net/www.sunarc.org.
authors: William B
authors: WB
authors: Grant
mesh_terms: D000236:Adenoma / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000097:blood*; D005260:Female; D006801:Humans; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Breast cancer; case-control study; colorectal adenoma; colorectal cancer; nested case-control study; vitamin D