Research from a variety of sources has suggested that GnRH agonists, a group of medications used as hormone therapy for treating uterine fibroids and other disorders of the female reproductive tract, are instrumental in reducing bone mineral density (BMD). BMD is used to determine the amount of bone loss in patients, and is an important index in predicting osteoporosis and the frequent, dangerous fractures with which the disease is associated.
|Reducing your risk of osteoporosis:|
Begin a lifelong commitment to exercise and eating right while you are young.
Exercise increases bone mass and reduces bone loss after menopause. To prevent bone loss, weight-bearing activities like walking, low impact aerobics, and tennis are best.
Adequate calcium intake is essential. Depending on your age, you need 1,000 to 1,300 mg of calcium a day. Good sources of calcium are dairy products, leafy green vegetables, nuts and seafood.
Vitamin D is necessary for the absorption of calcium. Milk fortified with Vitamin D and 10-15 minutes of sun exposure 2-3 times a week are excellent sources.
Avoid smoking and excessive alcohol and caffeine consumption.
One study, conducted by Dr. Sanjay K. Agarwal and colleagues at the University of California, Los Angeles and published in the July 2002 issue of The Journal of Reproductive Medicine, indicated that BMD loss from GnRH agonist therapy occurs at equal rates in young and old patients. These findings have important implications because they suggest that GnRH agonist therapy may present a special risk for younger women who have not yet reached peak BMD by preventing them from ever reaching a healthy peak level.
Another study, completed by Dr. Hiroya Matsuo of the Kobe University School of Medicine, in Kobe, Japan, and published in the January 2004 issue of Fertility and Sterility, focused on a group of 50 women who were receiving GnRH agonist therapy for endometriosis. The study showed that in addition to the reduction of BMD observed in patients, there was an increase in BMD post-treatment; but even a year after treatment, some of the women had failed to return to their pre-treatment BMD. This was true even though the women took calcium supplements during the treatment.
GnRH agonists work by reducing estrogen in the body, and estrogen affects bone absorption and renewal. Dr. Matsuo noted that although these findings highlight the likelihood of additional risks for BMD loss, the efficacy of "add-back" hormonal therapies to counteract the estrogen loss associated with a GnRH agonists has been supported by research in recent years, and that his team’s findings "might not apply to the patients who receive these drugs in conjunction with GnRH [agonists]." But, he added, "some patients hesitated to take hormonal agents because they fear adverse events such as the development of cancer and cardiovascular disease, and use of antiosteoporosis agents by premenopausal women is not approved…our findings may help patient selection."
In the body, two types of specialized cells work to maintain BMD. Bone is broken down by cells known as osteoclasts and regenerated by cells known as osteoblasts. Before women have reached their peak bone mineral density, the osteoblasts generate more bone than the osteoclasts can break down, resulting in net increases of BMD. After this point, osteoclast and osteoblast activity evens off, and eventually, the osteoclasts break down more bone than the osteoblasts, leading to net reductions of BMD. But reductions in estrogen or nutritional deficiency can throw this process off, causing BMD loss in younger patients.
BMD peaks in women sometime in their 30s, and becomes lower over time after this point. If women do not reach a healthy BMD level by the time their BMD is at its apex, they are at higher risk for osteoporosis as they age, and may suffer from earlier, more rapid onset of bone weakness or deterioration.