title: Plasma 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D and risk of incident ovarian cancer.
abstract: Few modifiable factors are known to reduce ovarian cancer risk. Ecologic studies and experimental data suggest that vitamin D may reduce ovarian cancer risk. Therefore, we examined whether plasma concentrations of 25-hydroxyvitamin D (a measure of overall vitamin D status) and 1,25-dihydroxyvitamin D (biologically active form) were associated with risk of epithelial ovarian cancer in a nested-case control study using data from three prospective cohorts: the Nurses' Health Study (NHS), NHSII, and the Women's Health Study (WHS). The analysis had 224 cases (161 from NHS/NHSII and 63 from WHS) and 603 controls (matching ratio, 1:3 for NHS/NHSII and 1:2 for WHS). Women ranged in age from 34 to 73 years (mean, 56 years). We did not observe significant associations between 25-hydroxyvitamin D [top versus bottom quartile: relative risk (RR), 0.83; 95% confidence interval (95% CI), 0.49-1.39; P(trend) = 0.57] or 1,25-dihydroxyvitamin D levels (RR, 1.14; 95% CI, 0.70-1.85, P(trend) = 0.93) and ovarian cancer risk. Study-specific associations were not statistically significant and no statistical heterogeneity existed between studies (P = 0.66, 25-hydroxyvitamin D; P = 0.40, 1,25-dihydroxyvitamin D). However, there was a significant inverse association among overweight and obese women for 25-hydroxyvitamin D levels (RR, 0.39; 95% CI, 0.16-0.93; P(trend) = 0.04). Further, those with adequate (>or=32 ng/mL) versus inadequate 25-hydroxyvitamin D levels had a modestly decreased risk of serous ovarian cancer (RR, 0.64; 95% CI, 0.39-1.05). Overall, our results do not suggest that plasma vitamin D levels are associated with risk of ovarian cancer. However, we observed significant associations in some subgroups, which should be evaluated further in other studies because increasing vitamin D intake is an easy preventive measure to adopt.
authors.affiliation: Channing Laboratory, Department of Medicine, Boston, MA 02115, USA. nhsst@channing.harvard.edu
authors.forename: Shelley S
authors.initials: SS
authors.lastname: Tworoger
authors.forename: I-Min
authors.initials: IM
authors.lastname: Lee
authors.forename: Julie E
authors.initials: JE
authors.lastname: Buring
authors.forename: Bernard
authors.initials: B
authors.lastname: Rosner
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Hollis
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hankinson
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood; D016022:Case-Control Studies; D004100:Dihydroxycholecalciferols / Q000097:blood*; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000097:blood* / Q000453:epidemiology; D012306:Risk; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014408:Biomarkers, Tumor; D004100:Dihydroxycholecalciferols; D014807:Vitamin D; C104450:25-hydroxyvitamin D