title: Prenatal DES exposure in relation to breast size.
abstract: OBJECTIVE
  Prenatal DES exposure has been associated with increased risk of breast cancer, but the mechanisms are unknown. Larger bra cup size has also been associated with increased breast cancer risk, although not consistently. We investigated the relation of prenatal DES exposure to mammary gland mass, as estimated by bra cup size.
  
  
  METHODS
  In 2006, 3,222 DES-exposed and 1,463 unexposed women reported their bra cup size, band size (chest circumference), and weight at age 20. Prevalence ratios (PR) were calculated for DES exposure in relation to large bra cup size, with control for year of birth and study cohort. Primary analyses were carried out among women who reported a chest circumference of no more than 32 inches because their cup size would be less influenced by fat mass.
  
  
  RESULTS
  Within this group, DES-exposed women had an estimated 45% increased prevalence (95% CI 0.97-2.18) of large cup size (C or greater) relative to unexposed women. The PR was further increased among women in this group who had a body mass index of < 21 at age 20: PR = 1.83 (95% CI 1.11-3.00). The PR for high-dose DES exposure relative to no exposure was 1.67, 95% CI 1.02-2.73, whereas there was no association of bra cup size with low-dose exposure.
  
  
  CONCLUSIONS
  These results provide support for the hypothesis that in utero DES exposure may result in greater mammary gland mass. Taken together with previous research on bra size and breast cancer risk, these findings suggest a mechanism for a possible association of in utero DES exposure with increased risk of breast cancer.
authors.affiliation: Slone Epidemiology Center at Boston University, 1010 Commonwealth Avenue, Boston, MA 02215, USA. jpalmer@bu.edu
authors.forename: Julie R
authors.initials: JR
authors.lastname: Palmer
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Boggs
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Hatch
authors.forename: Rebecca
authors.initials: R
authors.lastname: Troisi
authors.forename: Linda
authors.initials: L
authors.lastname: Titus-Ernstoff
authors.forename: William C
authors.initials: WC
authors.lastname: Strohsnitter
authors.forename: Ervin
authors.initials: E
authors.lastname: Adam
authors.forename: Robert N
authors.initials: RN
authors.lastname: Hoover
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D015331:Cohort Studies; D004054:Diethylstilbestrol / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D042361:Mammary Glands, Human / Q000033:anatomy & histology* / Q000254:growth & development; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D012307:Risk Factors; D055815:Young Adult
chemical_list: D004054:Diethylstilbestrol