Dear OhMary, After age 35, and particularly after menopause, bone resorption gradually begins to outstrip bone formation, resulting in a slow loss of bone mass. Over time, usually many years, bone mass reaches the low end of the
normalNormal saline flush range: osteopenia. If loss of bone mass continues long enough, osteoporosis is the result. Osteoporosis may be moderate, associated with an increased risk of fracture, or it can be severe, associated with actual fractures.
Loss of bone mass is an inherent part of the aging process of men and women, although it tends to affect women more. Our bone mass is less dense than men's to begin with, and we tend to live longer, allowing more time for bone aging. Bone mass is greatest in women's 20s and 30s; it stabilizes between 30 and 40, and over 40 there is slow loss of bone strength. After menopause, there is a five- to seven-year period of accelerated bone loss; then the rate slows and returns to an age-related rate.
The aging process has a greater effect on bone loss than the presence or absence of estrogen. Smoking, prolonged bed rest or inactivity, being underweight, and certain medications can increase bone loss (early menopause brought on by chemotherapy can produce significant loss of bone strength, starting during chemotherapy). Weight-bearing exercise increases bone mass. Tamoxifen tends to stabilize bone strength, but for the first year of taking it, pre-menopausal women may experience bone loss; post-menopausal women may have some bone strengthening. Discuss with your oncologist your individual situation, and what might be recommended in your case.