From the day we are born, we continue to build bone faster than it is broken down. This occurs up to age 25 to 30. As we get older, the rate of formation is less than the rate of breakdown. We are losing bone, but gradually as we get older. In women, because of menopause and the loss of estrogen, it occurs at about 52 years of age.
Women develop a more rapid loss during premenstrual and menopausal years.
All women should consider taking estrogen at menopause. Not every woman should be on estrogen if they have had a history of breast cancer or an immediate family member with a history of breast cancer, or if they are having severe effects from treatment. In general, women must make an individual assessment and weigh the risks vs. the benefits. Some feel there is a difference. I recommend utilizing what you tolerate best.