Medical Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Semin Reprod Med. 2010 Sep;28(5):422-5. doi: 10.1055/s-0030-1262901. Epub 2010 Sep 23.
The skeleton's density (mineral content and strength) is due to genetics (60%), nutrition (20%), and sex hormones (20%). The last factor increases bone density at puberty, mostly due to estrogen production. During reproductive aging as the ovaries lose most of their follicles, estrogen production declines. Bone collagen and mineral content decreases as the total cyclic estrogen production declines until the postmenopausal phase of life, at which point the 20% gained at puberty has been lost. This process starts before menses have changed, when fertility starts to be reduced. The most rapid loss of bone density occurs after actual menopause. Thereafter the rate of bone substance loss slows to the same rate as seen in aging men and is likely related to aging itself. In conclusion, decline in estrogen production is a major cause of bone mineral decrease.
骨骼的密度（矿物质含量和强度）主要由遗传因素（约 60%）、营养（约 20%）和性激素（20%）决定。最后一个因素在青春期增加骨密度，主要是由于雌激素的产生。在生殖衰老过程中，随着卵巢失去大部分卵泡，雌激素的产生下降。随着总循环雌激素的产生减少，骨胶原和矿物质含量减少，直到绝经后的生命阶段，此时青春期获得的 20%已经丢失。这个过程在月经改变之前就开始了，那时生育能力开始下降。骨密度最快的下降发生在实际绝经后。此后，骨质流失的速度减缓到与男性衰老相同的速度，这可能与衰老本身有关。总之，雌激素产生的下降是导致骨矿物质减少的主要原因。
