Epidemiology of Estrogen

摘要

Endogenous serum concentrations of estradiol in US caucasian women decline to a postmenopausal average of 5 to 10 pg/ml. About 1/3 have estradiol concentrations below 5 pg/ml. Levels in other racial groups and in other regions of the world are not well established. Estradiol concentrations in caucasian US men over age 50 are higher than in women, with an average between 15 to 25 pg/ml. thus, there is no basis for the belief that women have a lower rate of heart disease or longer lives because they have higher endogenous concentratiosn of estrogen. Endogenous estradiol is the most importnat hormonal determinant of bone density in women and men. complete Blockade of estradiol production causes apoptosis of ostecytes and raises markers of bone turnover. Women who have estradiol concentratiosn below 5 pg/ml have increased bone turnover and a three-fold greater risk of hip and vertebral fractures than women with higher concentrations of estradiol. Osteoporosis in men is commonly related to decreased estradiol and rarely, if ever, dueto testosteone deficiency alone. The lower rate of fractures in caucasian men than in caucasian women may be due, in part, to higher concentrations of estradiol in elderly men. Endogenous estradiol promotes breast and endometrial cancer. We have found that women with the highest levels of estradiol and testosterone (a precursor of estradiol) have > 10 times the risk of breast cancer as women who have very low or undertectable levels of both hormones.