title: Serum 25-hydroxyvitamin D and risk of breast cancer: results of a large population-based case-control study in Mexican women.
abstract: OBJECTIVE
  Epidemiologic studies have suggested that higher levels of circulating vitamin D may reduce breast cancer risk, but no studies have investigated this association among women in developing countries, and very few studies have further investigated this association according to menopausal status.
  
  
  METHODS
  A population-based case-control study in Mexico with 1,000 incident breast cancer cases aged 35-69 years, enrolled shortly after diagnosis (0-6 days) and frequency-matched to 1,074 controls on age, region, and health care system, was used to assess the association between serum 25-hydroxyvitamin D [25(OH)D] levels with overall, pre- and postmenopausal breast cancer risk. 25(OH)D concentration was measured on a random sub-sample of women (573 cases and 639 matched controls) using a liquid chromatography/tandem mass spectrometry method. Odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated from multivariable conditional logistic regression models.
  
  
  RESULTS
  Serum 25(OH)D concentration (per 10 ng/mL increase) showed a strong inverse association with risk of breast cancer among all (p(trend) = 0.001), pre- (p(trend) = 0.006) and postmenopausal women (p(trend) = 0.0001). Compared with a predefined lower concentration of 25(OH)D (<20 ng/mL), higher levels (>30 ng/mL) were associated with lower overall (OR = 0.53, 95 % CI: 0.28-1.00; p(trend) = 0.002), pre- (OR = 0.60, 95 % CI: 0.16-2.17; p(trend) = 0.07) and postmenopausal (OR = 0.37, 95 % CI: 0.16-0.82; p(trend) = 0.004) breast cancer risk.
  
  
  CONCLUSIONS
  The results of this large population-based case-control study indicate an inverse association between circulating vitamin D levels and breast cancer risk among pre- and postmenopausal Mexican women.
authors.affiliation: International Agency for Research on Cancer, Lyon, France.
authors.forename: Veronika
authors.initials: V
authors.lastname: Fedirko
authors.forename: Gabriela
authors.initials: G
authors.lastname: Torres-Mejía
authors.forename: Carolina
authors.initials: C
authors.lastname: Ortega-Olvera
authors.forename: Carine
authors.initials: C
authors.lastname: Biessy
authors.forename: Angelica
authors.initials: A
authors.lastname: Angeles-Llerenas
authors.forename: Eduardo
authors.initials: E
authors.lastname: Lazcano-Ponce
authors.forename: Vicente A
authors.initials: VA
authors.lastname: Saldaña-Quiroz
authors.forename: Isabelle
authors.initials: I
authors.lastname: Romieu
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000097:blood* / Q000453:epidemiology; D016022:Case-Control Studies; D002853:Chromatography, Liquid; D005260:Female; D006801:Humans; D016015:Logistic Models; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D015999:Multivariate Analysis; D011159:Population Surveillance / Q000379:methods; D012042:Registries / Q000706:statistics & numerical data*; D012307:Risk Factors; D011795:Surveys and Questionnaires; D053719:Tandem Mass Spectrometry; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D