Estrogen levels higher among black women during menstrual cycle
New data suggest that black women have higher levels of estradiol and lower androstenedione-to-estradiol ratios throughout the menstrual cycle compared with white women, a trend that may contribute to differences in the incidence and prevalence of health issues between these two populations.
Studies indicating higher incidences of estrogen-associated conditions, such as breast cancer and earlier puberty, among black women prompted researchers at Massachusetts General Hospital to compare levels of estradiol, progesterone, gonadotropins, androstenedione, inhibins and sex hormone-binding globulin (SHBG) in reproductive-aged black and white women during a full menstrual cycle. The researchers included 27 black women and 27 white women of similar age, BMI and normal menstrual cycles (average duration, 29.4 days).
Daily blood samples taken from study participants indicated higher levels of estradiol in black women vs. white women (P=.02). Cycle phase exerted considerable influence on these levels, according to the researchers. Differences between the black and white women peaked during the late follicular phase (225.2 pg/mL vs. 191.5 pg/mL, respectively; P=.02); the midluteal phase (211.9 pg/mL vs. 150.8 pg/mL; P<.001); and late luteal phase (144.4 pg/mL vs. 103.5 pg/mL; P=.01).
Androstenedione, luteinizing hormone, follicle-stimulating hormone, inhibin A, inhibin B and SHBG did not differ significantly between study groups. However, the androstenedione-to-estradiol ratio was notably lower in black women (P<.001). These results may denote enhanced aromatase activity in this population, which may be responsible for racial disparities in bone mineral density, breast cancer and uterine leiomyomas, the researchers said.
“Further studies will be needed to address this hypothesis more directly and to address possible effects of race on estrogen feedback dynamics,” the researchers wrote. “However, the findings from the current studies provide important insights into potential mechanisms underlying the health disparities in [African-American women] and [Caucasian women] documented in epidemiological studies by suggesting that [African-American women] may have a greater lifetime exposure to estrogens.”
Disclosure: The researchers report no relevant financial disclosures.
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