Starting at an early age, our goal should be to prevent osteoporosis before our bones reach that stage when they weaken and become thin. This means maximizing our bone calcium during adolescence; maintaining bone calcium during adulthood; and for women, minimizing postmenopausal bone loss. Bone calcium increases in children and adolescents who consume higher levels of calcium in food or supplements. However, high calcium intake during the postmenopausal period has no effect—or a minimal protective effect—against bone loss in women. (Men also get osteoporosis, but in smaller numbers.)
To maintain bone strength, most adults should have 1000 to 1500 mg of calcium per day. In addition, regular weight-bearing exercise, like walking, contributes to the development of bone mass, and resistance or impact exercise, such as lifting weights, helps maintain bone mineral levels.
In Caucasian women, calcium intake should be 800 mg a day until age ten, then 1,500 mg during adolescence and pregnancy, and 1,200 mg during adulthood. Vitamin D, 400 to 800 IU, is a valuable supplement used in conjunction with calcium supplements. This is particularly helpful for the elderly who have limited exposure to sunlight, or nutritional deficiency. The combination of these supplements decreases the risk of hip fractures in elderly populations. Non-Caucasian women start with a greater amount of bone mineral calcium. They should take calcium supplements, but they are at less risk for fractures.
Hormone Replacement Therapy for Women
The reason osteoporosis is considered a women’s health issue is because estrogen deficiency after menopause leads to bone loss. The greatest rate of bone loss occurs in the first years after cessation of ovarian function. Estrogen replacement therapy, commonly called ERT, is often started soon after the onset of menopause in women who are appropriate candidates. Some women begin hormonal therapy during the perimenopausal periods. ERT is not recommended if you have a history of breast or uterine cancer or clotting disorders. To prevent bone loss with ERT, women need estrogen every day. For women with an intact uterus, progesterone is added because it decreases the risk of uterine cancer. This combination therapy is called HRT, hormone replacement therapy. The Women’s Health Initiative, a large, national study of women taking estrogen and progesterone replacement therapy, reported an increase in cardiovascular disease and breast cancer in the group taking HRT. The study was stopped prematurely because of the concerns regarding the ill effects of HRT. The appropriate role of HRT remains very much in question. The use of HRT is a personal choice that must be discussed with your physician.
Raloxifene (Evista) is a selective estrogen-receptor modulator (SERM) with estrogen like effects on bone resorption but without stimulating breast tissue or the lining of the uterus in postmenopausal women. Raloxifene, given in daily doses, effectively increases bone and decreases the risk of spine and hip fracture. Toxic side effects include hot flashes, leg cramps, and rare episodes of venous clotting.
Calcitonin is a hormone that reduces bone breakdown and is used to treat osteoporosis, and salmon calcitonin is more effective than human calcitonin. Calcitonin is given by injection, or intranasally, on a daily basis. Nasal calcitonin decreases the risk of spinal fractures but may not significantly alter the risk of hip fractures. However, one of the added benefits of calcitonin is its pain-relieving effects, particularly on bone fractures.
Bisphosphonates came into medical use in a roundabout way, and their concept is based on research that studied detergents and hard water. Bisphosphonates attach to bone crystals, the sites of active bone remodeling. Bones are living tissues, constantly being built up and torn down, and bisphosphonates alter bone remodeling by reducing the tearing down portion of remodeling. By decreasing bone resorption, bone density is increased.
Alendronate (Fosamax) effectively prevents and treats osteoporosis because alendronate is a potent inhibiting agent of bone remodeling. Studies of women with established osteoporosis have found that alendronate given every day prevents postmenopausal bone loss and increases bone density in the spine by approximately 4 to 6 percent over a three year period. Alendronate also has a beneficial effect on increasing bone density in the hip. A smaller daily dose of alendronate is comparable to ERT in preventing bone loss. The effect on bone is prolonged, meaning that it’s measured in years; therefore, younger women of childbearing years are not candidates for this agent. Alendronate comes in a larger-dose pill that allows administration once a week with the same beneficial effects as the daily dose. The larger dose formulation is more convenient than the smaller daily dose. This weekly regimen decreases exposure of the esophagus and, hence, reduces irritation.
Risedronate (Actonel) decreases the risk of spine and hip fractures as well as increasing bone in these locations. This drug has been recently approved by the FDA for the treatment of postmenopausal osteoporosis at a single daily dose. Actonel, a once-weekly pill has also been approved.
The primary toxicity of the bisphosphonates is gastrointestinal, and they tend to have poor intestinal absorption. These drugs must be taken on an empty stomach. For example, alendronate should be taken in the morning after an overnight fast, with a large glass of water. In addition, you should remain upright for thirty minutes to assure that the medication remains out of the esophagus, because heartburn is a common complaint.