Posted on August 31, 2011
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.