Dear Patricia:

Estrogen plays a very large role, if not the primary role, in the development of osteoporosis. Many studies show that as women enter menopause and the ovaries stop producing estrogen, lower estrogen blood levels lead to accelerated bone loss, which can lead to osteoporosis. This process occurs right after the onset of menopause and lasts for about 10 years. During this time, bone loss can vary from less than 1% per year to above 5% per year, with an average of 2% per year.

Throughout life, our bones are in a constant state of resorption and formation, called bone remodeling. There are several ways that estrogen is thought to affect this process.

Bone resorbing cells called osteoclasts remove old bone by releasing acids and enzymes to scour out minerals and collagen. Once the osteoclasts have done their job, protein-secreting cells called osteoblasts pull calcium, magnesium, and phosphorus from the blood to build new bone tissue. Lack of estrogen appears to enhance the ability of osteoclasts to absorb bone and limit the absorption of calcium needed for osteoblasts to build bone. When the bone-removing osteoclasts do their job better than the bone-building osteoblasts, the net result is bone loss.

The potential benefits of estrogen replacement therapy are clear. ERT has been shown to prevent bone loss, increase bone mass, and prevent bone fractures in postmenopausal women and in women who have already developed osteoporosis. It is believed that hormone replacement therapy could potentially prevent 80% of vertebral fractures and reduce hip fractures by about 50%.

Educating women on health care options is the personal mission of Marla Ahlgrimm, R.Ph., founder and CEO of Women's Health America. If you have a women's health care question, send it to Marla at This e-mail address is being protected from spambots, you need JavaScript enabled to view it . If your question is chosen for publication, we'll send you a free sample of one of our latest health care innovations.