title: Do thyroid disorders increase the risk of breast cancer?
abstract: The objective of this study was to determine whether thyroid disorders or treatment of such disorders affects the risk of breast cancer. Subjects aged 35-64 years were participants in the National Institute of Child Health and Human Development Women's Contraceptive and Reproductive Experiences Study, a population-based, case-control study of invasive breast cancer that was carried out at five sites in the United States. In-person interviews were completed for 4575 women (cases) with breast cancer (2953 white and 1622 black) and 4682 control women (3021 white and 1661 black). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multiple logistic regression methods. Models included adjustment for age (5-year age groups), race (white or black), and site. A history of any thyroid disorder (OR = 1.1, 95% CI = 0.9-1.2) was not associated with breast cancer risk. Only women with a history of thyroid cancer had an increased risk, but this was restricted to parous women (parous OR = 3.4, 95% CI = 1.5-8.1; nulliparous OR = 0.5, 95% CI = 0.04-5.1). Breast cancer risk was not associated with treatment for thyroid disorders. There was no statistical interaction between thyroid disorders, thyroid treatments, and race, menopausal status, or parity. We found no association between thyroid disorders or their associated treatments and the risk of breast cancer.
authors.affiliation: Division of Hematology and Oncology, Karmanos Cancer Institute at Wayne State University, Detroit, Michigan, USA. Simonm@karmanos.org
authors.forename: Michael S
authors.initials: MS
authors.lastname: Simon
authors.forename: Mei-Tzu C
authors.initials: MT
authors.lastname: Tang
authors.forename: Leslie
authors.initials: L
authors.lastname: Bernstein
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Norman
authors.forename: Linda
authors.initials: L
authors.lastname: Weiss
authors.forename: Ronald T
authors.initials: RT
authors.lastname: Burkman
authors.forename: Janet R
authors.initials: JR
authors.lastname: Daling
authors.forename: Dennis
authors.initials: D
authors.lastname: Deapen
authors.forename: Suzanne G
authors.initials: SG
authors.lastname: Folger
authors.forename: Kathi
authors.initials: K
authors.lastname: Malone
authors.forename: Polly A
authors.initials: PA
authors.lastname: Marchbanks
authors.forename: Jill A
authors.initials: JA
authors.lastname: McDonald
authors.forename: Brian L
authors.initials: BL
authors.lastname: Strom
authors.forename: Hoyt G
authors.initials: HG
authors.lastname: Wilson
authors.forename: Robert
authors.initials: R
authors.lastname: Spirtas
mesh_terms: D000328:Adult; D017677:Age Distribution; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D016022:Case-Control Studies; D015331:Cohort Studies; D015897:Comorbidity; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011379:Prognosis; D012016:Reference Values; D018570:Risk Assessment; D012307:Risk Factors; D013959:Thyroid Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy