First Pregnancy Characteristics, Postmenopausal Breast Density, and Salivary Sex Hormone Levels in a Population at High Risk for Breast Cancer
Published Date:Jun 2015
Source:BBA Clin. 3:189-195.
Pubmed Central ID:PMC4547694
Funding:H75 DP001730/DP/NCCDPHP CDC HHS/United States
HHSN261201100031C/CA/NCI NIH HHS/United States
P01 CA154292/CA/NCI NIH HHS/United States
U01 CA063740/CA/NCI NIH HHS/United States
It remains unknown if later life breast cancer risk as determined by reproductive history is mediated by postmenopausal breast density and/or sex steroid levels.
Increased breast density is a strong surrogate for future breast cancer risk. A cross-sectional study with a longitudinal follow up for breast health outcomes evaluated women without breast cancer (n = 1,023; 682 = parous), drawn from a high risk postmenopausal population, with questionnaire reported reproductive histories. The questionnaire was linked to prospective screening mammogram breast density measurements, and saliva biospecimens that were used to assess sex steroid hormone levels.
Expected age and postmenopause related declines in salivary estradiol (E), progesterone (P), dehydroepiandrosterone (DHEA) and testosterone (T) levels were observed. This was most pronounced for DHEA and T, which were also the only postmenopausal hormone levels significantly associated with any reproductive characteristics: parity and breast feeding for DHEA, age-at-first birth for T. Postmenopausal breast density was borderline significantly lower with parity and higher body mass index (BMI). After multivariate analysis, T was the only hormone level to retain any association (negative, p<0.05) with breast density.
Conclusions and General Significance
While reproductive characteristics, in particular parity, generally demonstrated independent associations with postmenopausal breast density and E, P and DHEA levels, T levels showed concordant inverse associations with age-at-first birth and breast density. These findings suggest that reproductive effects and later life salivary sex steroid hormone levels may have independent effects on later life breast density and cancer risk.
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