title: Pre-diagnostic plasma 25-hydroxyvitamin D levels and risk of non-melanoma skin cancer in women.
abstract: BACKGROUND
  Recent reports have shown that vitamin D status was inversely associated with the risk of various cancers. However, few studies examined the association between vitamin D levels and risk of skin cancer.
  
  
  METHODS
  We prospectively evaluated the association between baseline plasma 25(OH)D levels and the risk of incident squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) among 4,641 women from the Nurses' Health Study (NHS) and the NHS II with 510 incident BCC cases and 75 incident SCC cases. We used multivariate logistic regression models to calculate odds ratios (ORs) and 95% confidence intervals (CIs).
  
  
  RESULTS
  Plasma 25(OH)D levels were positively associated with risk of BCC after adjusting for age at blood draw, season of blood draw, lab batch, hair color, burning tendency, the number of sunburns, and ultra-violet B flux of residence at blood collection. Women in the highest quartile of 25(OH)D had more than 2-fold increased risk of BCC compared with women in the lowest quartile (OR = 2.07, 95% CI = 1.52-2.80, P for trend <0.0001). We also found a significantly positive association between plasma 25(OH)D levels and SCC risk after adjusting for the same covariates (OR, highest vs. lowest quartile = 3.77, 95% CI = 1.70-8.36, P for trend= 0.0002).
  
  
  CONCLUSIONS
  In this prospective study of women, plasma vitamin D levels were positively associated with non-melanoma skin cancer risk. Considering that most circulating vitamin D is due to sun exposure, the positive association between plasma vitamin D and non-melanoma skin cancer is confounded by sun exposure. Our data suggest that one-time measurement of plasma vitamin D levels may reasonably reflect long-term sun exposure and predict the risk of non-melanoma skin cancer.
authors.affiliation: Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing, China.
authors.forename: Geyu
authors.initials: G
authors.lastname: Liang
authors.forename: Hongmei
authors.initials: H
authors.lastname: Nan
authors.forename: Abrar A
authors.initials: AA
authors.lastname: Qureshi
authors.forename: Jiali
authors.initials: J
authors.lastname: Han
mesh_terms: D000328:Adult; D000368:Aged; D002280:Basal Cell Carcinoma / Q000097:blood* / Q000453:epidemiology; D002294:Carcinoma, Squamous Cell / Q000097:blood* / Q000453:epidemiology; D016022:Case-Control Studies; D005260:Female; D006200:Hair Color; D006306:Health Surveys; D006801:Humans; D008875:Middle Aged; D009726:Nurses; D016017:Odds Ratio; D011446:Prospective Studies; D012044:Regression Analysis; D012306:Risk; D012621:Seasons; D012878:Skin Neoplasms / Q000097:blood* / Q000453:epidemiology; D013471:Sunburn; D014481:United States; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D