Listen as Dr. Siris explains how hormone replacement therapy (HRT) affects a woman's bones.
As long as a woman is producing her own estrogen, the regulation of bone removal in bone formation is in very, very good balance. Our bones get worn out and the body is very good at removing old bone and replacing it with an equivalent amount of new bone and this goes on every single day. It’s a little bit of bone is taken away and beautiful new bone is laid down or replaced it over about a three month period. Over eight years you fully replace your skeleton, that’s kind of interesting.
As long as you’re making estrogen, this is in perfect balance. When you get to menopause and your estrogen levels get very low, the system goes crazy. Too much bone is removed, it’s unregulated and although bone formation tries to keep up, it can’t.
So you lose bone and you damage bone in the process. If a woman is given estrogen because she needs it for hot flashes or she needs it for some other reason, her bones think she is back as a pre-menopausal woman and the regulation will go back to what it was before. The alternative drugs to estrogen that are given for bone do pretty much what estrogen did but not through an estrogen mechanism.
About Dr. Ethel Siris, M.D.:
Dr. Ethel S. Siris is the Director at the Toni Stabile Osteoporosis Center, Columbia University, is the Madeline C. Stabile Professor of Medicine at Columbia University, and is the immediate past-President for the National Osteoporosis Foundation. She is board certified in endocrinology and internal medicine, focusing on osteoporosis, metabolic bone disease, and bone and mineral metabolism.