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

Abstract

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 post-menopausal 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 pre-menopausal (% difference=2.00 percentage points 95% CI:(−1.33,5.33)) or among post-menopausal 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.

Evaluation of the association of endometriosis and mammographic breast density, a cross-sectional study

“…It also infers that sex hormones alone are not implicated in female cancers after endometriosis. To the best of our knowledge, the only study which evaluated the relationship between endometriosis and MBD was that of Farland et al [15]. According to this study, endometriosis was not found to be associated with mammographic density, which was in contrast with our nding.…”

Evaluation of the association of endometriosis and mammographic breast density, a cross-sectional study

“…It also infers that sex hormones alone are not implicated in female cancers after endometriosis. To the best of our knowledge, the only study which evaluated the relationship between endometriosis and MBD was that of Farland et al [ 20 ]. According to this study, endometriosis was not found to be associated with mammographic density, which was in contrast with our finding.…”