title: Serum 25(OH)-vitamin D concentration and risk of esophageal squamous dysplasia.
abstract: BACKGROUND
  Squamous dysplasia is the precursor lesion for esophageal squamous cell carcinoma, and nutritional factors play an important role in the etiology of this cancer. Previous studies using a variety of measures for vitamin D exposure have reached different conclusions about the association between vitamin D and the risk of developing esophageal cancer.
  
  
  METHODS
  We measured serum 25-hydroxyvitamin D [25(OH)D] concentrations in a cross-sectional analysis of 720 subjects from Linxian, China, a population at high risk for developing esophageal squamous cell carcinoma. All subjects underwent endoscopy and biopsy and were categorized by the presence or absence of histologic squamous dysplasia. We used crude and multivariate-adjusted generalized linear models to estimate the relative risks (RR) and 95% confidence intervals (95% CI) for the association between squamous dysplasia and sex-specific quartiles of serum 25(OH)D concentration.
  
  
  RESULTS
  Two-hundred and thirty of 720 subjects (32%) had squamous dysplasia. Subjects with dysplasia had significantly higher median serum 25(OH)D concentrations than subjects without dysplasia, 36.5 and 31.5 nmol/L, respectively (Wilcoxon two-sample test, P = 0.0004). In multivariate-adjusted models, subjects in the highest compared with the lowest quartiles were at a significantly increased risk of squamous dysplasia (RR, 1.86; 95% CI, 1.35-2.62). Increased risks were similar when examined in men and women separately: men (RR, 1.74; 95% CI, 1.08-2.93); women (RR, 1.96; 95% CI, 1.28-3.18).
  
  
  CONCLUSIONS
  Higher serum 25(OH)D concentrations were associated with significantly increased risk of squamous dysplasia. No obvious source of measured or unmeasured confounding explains this finding.
authors.affiliation: Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, 6120 Executive Boulevard, EPS/320, MSC 7232, Rockville, MD 20852, USA. abnetc@mail.nih.gov
authors.forename: Christian C
authors.initials: CC
authors.lastname: Abnet
authors.forename: Wen
authors.initials: W
authors.lastname: Chen
authors.forename: Sanford M
authors.initials: SM
authors.lastname: Dawsey
authors.forename: Wen-Qiang
authors.initials: WQ
authors.lastname: Wei
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Roth
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.forename: Ning
authors.initials: N
authors.lastname: Lu
authors.forename: Philip R
authors.initials: PR
authors.lastname: Taylor
authors.forename: You-Lin
authors.initials: YL
authors.lastname: Qiao
mesh_terms: D000328:Adult; D000367:Age Factors; D014408:Biomarkers, Tumor; D004938:Esophageal Neoplasms / Q000097:blood / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000097:blood / Q000209:etiology*; D012306:Risk; D012307:Risk Factors; D012737:Sex Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014408:Biomarkers, Tumor; D014807:Vitamin D; C104450:25-hydroxyvitamin D