Endometriosis and mammographic density measurements in the Nurses’ Health Study II

Leslie V. Farland, Rulla M. Tamimi, A. Heather Eliassen, Donna Spiegelman, Kimberly A. Bertrand, Stacey A. Missmer

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Purpose: Endometriosis and mammographic density have been hypothesized to be influenced by sex steroid hormonal exposures in adolescence and early adulthood. We investigated the association between endometriosis and mammographic density, a consistent and independent risk factor for breast cancer. Methods: We conducted a cross-sectional analysis among 1,581 pre- and postmenopausal women not previously diagnosed with breast cancer in the Nurses’ Health Study II cohort. We measured average percent mammographic density and absolute dense and non-dense breast area using a validated computer-assisted method. Multivariable linear regression was used to estimate the association between endometriosis and mammographic density among pre- and postmenopausal women separately. Results: Among premenopausal women, average percent mammographic density was 43.1 % among women with endometriosis (n = 91) and 40.5 % among women without endometriosis (n = 1,150). Endometriosis was not associated significantly with mammographic density among premenopausal (% difference = 2.00 percentage points 95 % CI −1.33, 5.33) or among postmenopausal women (% difference = −0.89 percentage points 95 % CI −5.10, 3.33). Among premenopausal women, there was heterogeneity by BMI at age 18 (p value = 0.003), with a suggested association among those who were lean at age 18 (BMI < 20.6 kg/m2) (% difference = 3.74 percentage points 95 % CI −0.29, 7.78). Conclusion: Endometriosis was not found to be associated with overall measurements of mammographic density.

Original languageEnglish (US)
Pages (from-to)1229-1237
Number of pages9
JournalCancer Causes and Control
Issue number10
StatePublished - Oct 1 2016


  • Breast cancer
  • Breast density
  • Endometriosis
  • Epidemiology
  • Mammographic density

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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