While some bone is lost each year, the rate of bone loss increases dramatically in the five to 10 years after menopause. Then, for several years, the breakdown of bone occurs at a much greater pace than the building of new bone. This is the process that eventually causes osteoporosis.
During this time, even though your bones may still be strong enough to prevent unusual fractures and you have no signs to alert you to the disease, bone loss may become detectable with a bone density test.