Baseline estrogen levels in postmenopausal women participating in the MAP.3 breast cancer chemoprevention trial

Abstract

Objective: The aim of the study was to quantify baseline estradiol (E2) and estrone (E1) concentrations according to selected patient characteristics in a substudy nested within the MAP.3 chemoprevention trial. Methods: E2 and E1 levels were measured in 4,068 postmenopausal women using liquid chromatography-tandem mass spectrometry. Distributions were described by age, years since menopause, race, body mass index (BMI), smoking status, and use and duration of hormone therapy using the Kruskal-Wallis test. Multivariable linear regression was also used to identify characteristics associated with estrogen levels. Results: After truncation at the 97.5th percentile, the mean (SD)/median (IQR) values for E2 and E1 were 5.41 (4.67)/4.0 (2.4-6.7) pg/mL and 24.7 (14.1)/21 (15-31) pg/mL, respectively. E2 and E1 were strongly correlated (Pearson correlation [r] = 0.8, P < 0.01). The largest variation in E2 and E1 levels was by BMI; mean E2 and E1 levels were 3.5 and 19.1 pg/mL, respectively for women with BMI less than 25 and 7.5 and 30.6 pg/mL, respectively, for women with BMI greater than 30. E2 and E1 varied by age, BMI, smoking status, and prior hormone therapy in multivariable models (P < 0.01). Conclusions: There was large interindividual variability observed for E2 and E1 that varied significantly by participant characteristics, but with small absolute differences except in the case of BMI. Although the majority of participant characteristics were independently associated with E1 and E2, together, these factors only explained about 20% of the variation in E1 and E2 levels.

The Impact of Estrogens and Their Receptors on Immunity and Inflammation during Infection

“…Estrogen levels in females are lower after menopause ( Figure 2 ) [ 134 ]. In general, menopause, and the subsequent reduction in estrogen, is associated with an increase in inflammation and the development of chronic conditions in a variety of organ systems [ 135 , 136 , 137 ].…”

Genome-wide Association Study of Estradiol Levels and the Causal Effect of Estradiol on Bone Mineral Density

“…However, in premenopausal women, estradiol levels vary during the menstrual cycle, limiting our ability to estimate the genetic effects on estradiol in females. In postmenopausal women, on the other hand, estradiol levels drop rapidly, and it has previously been suggested that the estradiol levels in females are more likely to be determined by the number of years since menopause ( 42 ). For those reasons, we performed sensitivity analyses, stratifying females by menopausal status and adjusting for age at menopause in the postmenopausal strata.…”

Genome-Wide Association Study of Estradiol Levels, and the Causal Effect of Estradiol on Bone Mineral Density

“…However, in premenopausal women, estradiol levels vary during the menstrual cycle, limiting our ability to estimate the genetic effects on estradiol in females. In postmenopausal women, on the other hand, estradiol levels drop rapidly, and it has previously been suggested that the estradiol levels in females are more likely to be determined by the number of years since menopause 39 . For those reasons, we performed sensitivity analyses, stratifying females by menopausal status, and also adjusting for age at menopause in the postmenopausal strata.…”