title: Selenium and risk of bladder cancer: a population-based case-control study.
abstract: Emerging evidence indicates a potential role of selenium in the prevention of several types of cancer, including bladder cancer. We investigated the association between toenail selenium concentrations and bladder cancer risk in a population-based case-control study in New Hampshire. We analyzed data from 857 incidence cases diagnosed between July 1, 1994 and June 30, 2001 and 1,191 general population controls. Newly diagnosed cases of bladder cancer were identified from the New Hampshire State Cancer Registry, which operates a rapid reporting system. Controls were selected from population lists (driver's license and Medicare enrollment). We used logistic regression analyses to generate odds ratios (OR) and 95% confidence intervals (95% CI), controlling for age, sex, and pack-years of smoking and conducted separate analyses according to the intensity of p53 immunohistochemical staining of the tumor. Overall, toenail selenium concentrations were not significantly related to bladder cancer [OR Q4 versus Q1, 0.90 (95% CI, 0.68-1.19); P(trend) = 0.15]. However, within specific subgroups there were inverse associations, i.e., among moderate smokers [OR, 0.61 (95% CI, 0.39-0.96); P(trend) = 0.004], women [OR, 0.66 (95% CI, 0.40-1.10); P(trend) = 0.11], and those with p53-positive cancers [OR Q4 versus Q1, 0.57 (95% CI, 0.34-0.94); P(trend) = 0.01]. Our results indicate that selenium is not inversely related to risk of bladder cancer overall; however, they raise the possibility that selenium may be preventive in certain molecular phenotypes of tumors (e.g., p53 positive) or within certain subsets of a population (e.g., women or moderate smokers).
authors.affiliation: Department of Community and Family Medicine, Section of Biostatistics and Epidemiology, Dartmouth Medical School, 7927 Rubin Building, 1 Medical Center Drive, Lebanon, NH 03756, USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Wallace
authors.forename: Karl T
authors.initials: KT
authors.lastname: Kelsey
authors.forename: Alan
authors.initials: A
authors.lastname: Schned
authors.forename: J Steven
authors.initials: JS
authors.lastname: Morris
authors.forename: Angeline S
authors.initials: AS
authors.lastname: Andrew
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Karagas
mesh_terms: D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009262:Nails / Q000737:chemistry; D012307:Risk Factors; D012643:Selenium / Q000032:analysis*; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology* / Q000378:metabolism
chemical_list: D016159:Tumor Suppressor Protein p53; D012643:Selenium