title: The association between selenium and other micronutrients and thyroid cancer incidence in the NIH-AARP Diet and Health Study.
abstract: BACKGROUND
  Selenium is an essential trace element that is important for thyroid hormone metabolism and has antioxidant properties which protect the thyroid gland from oxidative stress. The association of selenium, as well as intake of other micronutrients, with thyroid cancer is unclear.
  
  
  METHODS
  We evaluated associations of dietary selenium, beta-carotene, calcium, vitamin D, vitamin C, vitamin E, folate, magnesium, and zinc intake with thyroid cancer risk in the National Institutes of Health - American Association of Retired Persons Diet and Health Study, a large prospective cohort of 566,398 men and women aged 50-71 years in 1995-1996. Multivariable-adjusted Cox proportional hazards regression was used to examine associations between dietary intake of micronutrients, assessed using a food frequency questionnaire, and thyroid cancer cases, ascertained by linkage to state cancer registries and the National Death Index.
  
  
  RESULTS
  With the exception of vitamin C, which was associated with an increased risk of thyroid cancer (HR(Q5 vs Q1), 1.34; 95% CI, 1.02-1.76; P(trend), <0.01), we observed no evidence of an association between quintile of selenium (HR(Q5 vs Q1), 1.23; 95% CI, 0.92-1.65; P(trend), 0.26) or other micronutrient intake and thyroid cancer.
  
  
  CONCLUSIONS
  Our study does not suggest strong evidence for an association between dietary intake of selenium or other micronutrients and thyroid cancer risk. More studies are needed to clarify the role of selenium and other micronutrients in thyroid carcinogenesis.
authors.affiliation: University at Albany, School of Public Health, Rensselaer, New York, United States of America.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: O'Grady
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Cari M
authors.initials: CM
authors.lastname: Kitahara
authors.affiliation: University at Albany, School of Public Health, Rensselaer, New York, United States of America.
authors.forename: A Gregory
authors.initials: AG
authors.lastname: DiRienzo
authors.affiliation: University at Albany, School of Public Health, Rensselaer, New York, United States of America.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Gates
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D054547:National Cancer Institute (U.S.); D011446:Prospective Studies; D012307:Risk Factors; D012643:Selenium / Q000008:administration & dosage* / Q000009:adverse effects; D011795:Surveys and Questionnaires; D013964:Thyroid Neoplasms / Q000453:epidemiology*; D014131:Trace Elements / Q000008:administration & dosage* / Q000009:adverse effects; D014481:United States / Q000453:epidemiology
chemical_list: D014131:Trace Elements; D012643:Selenium