title: Diabetes and thyroid cancer risk in the National Institutes of Health-AARP Diet and Health Study.
abstract: BACKGROUND
  We hypothesized that diabetes may play a role in thyroid cancer risk due to the parallel secular rise in diabetes prevalence and morbidity in the United States, the higher prevalence of thyroid disorders among diabetics compared with the general population, and the potential roles of metabolic syndrome, obesity, and diabetes as precipitating factors in cancer development.
  
  
  METHODS
  We assessed the association between self-reported diabetes and the risk of differentiated thyroid cancer in the NIH-AARP Diet and Health Study, a prospective cohort of 200,556 women and 295,992 men, 50-71 years of age, in 1995-1996. Diabetes status and information on potential confounders was ascertained using a self-administered questionnaire. During an average of 10 years of follow-up, 585 thyroid cancer cases were identified. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for thyroid cancer and thyroid cancer subtypes in men and women according to diabetes status.
  
  
  RESULTS
  Nine percent of the total baseline cohort reported a history of diabetes (7% of women, 10% of men). A nonsignificant 25% increase in thyroid cancer risk (HR = 1.25; 95% CI: 0.95-1.64) was associated with diabetes. Among women, the risk was significantly increased (HR = 1.46, 95% CI: 1.01-2.10). The risk was not elevated among men (HR = 1.04, 95% CI: 0.69-1.58). In this cohort, diabetic women with differentiated thyroid cancer were at somewhat higher risk of follicular thyroid cancer (HR = 1.92; 95% CI: 0.86-4.27) than papillary thyroid cancer (HR = 1.25; 95% CI: 0.80-1.97).
  
  
  CONCLUSIONS
  This study lends support to the hypothesis that diabetes increases the risk of differentiated thyroid cancer.
authors.affiliation: Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, Maryland 20892, USA. kilfoyb@mail.nih.gov
authors.forename: Briseis
authors.initials: B
authors.lastname: Aschebrook-Kilfoy
authors.forename: Mona M
authors.initials: MM
authors.lastname: Sabra
authors.forename: Alina
authors.initials: A
authors.lastname: Brenner
authors.forename: Steven C
authors.initials: SC
authors.lastname: Moore
authors.forename: Elaine
authors.initials: E
authors.lastname: Ron
authors.forename: Arthur
authors.initials: A
authors.lastname: Schatzkin
authors.forename: Albert
authors.initials: A
authors.lastname: Hollenbeck
authors.forename: Mary H
authors.initials: MH
authors.lastname: Ward
mesh_terms: D018263:Adenocarcinoma, Follicular; D000367:Age Factors; D000368:Aged; D000375:Aging; D002277:Carcinoma; D002291:Carcinoma, Papillary; D002454:Cell Differentiation; D048909:Diabetes Complications / Q000453:epidemiology*; D003920:Diabetes Mellitus / Q000453:epidemiology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009316:National Institutes of Health (U.S.); D015995:Prevalence; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000453:epidemiology* / Q000473:pathology; D013997:Time Factors; D014481:United States / Q000453:epidemiology