Our expert is Robert W. Downs, Jr., MD, Professor of Medicine and Acting Chair, Division of Endocrinology and Metabolism, Virginia Commonwealth University. Dr. Downs is Deputy Editor of Journal of Women’s Health.
This blog post came about because of a reader request. We’ve already featured an article with Dr. Ethel Siris on preventing osteoporosis, but the reader wanted information on diagnosing the condition and what to do for patients who already have it.
My goal in this blog is to provide you the latest medical research on topics that are important to you, so if there’s a story you’d like to see covered, please let me know!
Best to all of you,
DIAGNOSING OSTEOPOROSIS: WHAT THE T-SCORES MEAN–AND DON’T MEAN
T-score bone density ratings were initially designed by the World Health Organization (WHO) to assist with studies of osteoporosis in populations, but are now also used for assessment of individual fracture risk. The scores are calibrated against the bone density of a normal 25- or 30-year old man or woman. The bone density of a healthy average 30-year old woman on this scale would thus be 0. An individual whose bone density is one standard deviation below the average would be -1, and a score two standard deviations below average would be -2. In the case of women after menopause, it’s not uncommon to find a T-score of -2.5 or lower. We say that an individual with a T-score of -2.5 or lower has Osteoporosis, but individuals with a higher score might still be at risk for osteoporotic fractures.
THE FRAX 10-YEAR FRACTURE RISK
To estimate the risk of fracture, we consider bone density along with other risk factors including: age, family history, previous fractures, whether she has ever smoked, whether she’s taken steroids, and her drinking habits. The WHO FRAX 10-Year Fracture Risk Calculator(™) calculates an individual’s risk for fracture, and then that risk can be used to determine whether the risk is great enough to warrant treatment. You can find it online here. In the U.S., the National Osteoporosis Foundation has suggested in their guidelines that if there is greater than 3% risk for a hip fracture or a 20% risk for a major osteoporotic fracture such as a spine fracture in the next 10 years, we can consider treatment to be worthwhile. Three percent may sound like a low risk in the course of 10 years, but if you have 10,000 people and 300 of them end up with a hip fracture, that’s a large number of people who may need hospitalization and who may end up spending the rest of their days in a nursing home. From clinical trials we know that treatment may decrease these fractures by 50% and thus many would avoid the long-term care and disability.
WHAT CAN BE DONE FOR A PATIENT WITH OSTEOPOROSIS?
We know from large-scale double-blind clinical trials that currently available pharmacological treatments can result in a 50% reduction in bone fracture risk. Even in the case of those with severe osteoporosis, we see a reduction in their risk within 6 months after treatment was initiated. There’s excellent data showing that even when you might intuitively think bone density is too low for the individual to benefit from treatment, medication can still result in some strengthening of bone and reduction of fracture risk.
HOW THE COMMON MEDICATIONS WORK
Up until menopause, a woman’s estrogen helps maintain a balance between the osteoclast cells that break down bones and the osteoblast cells that remineralize bones. After menopause, decreased estrogen means the osteoclasts are no longer as effectively kept in check. To visualize what’s going on, imagine bones being a city street that keeps getting potholes. However, there are road crews, in this case, the osteoblasts, that are trying to fill in the potholes as fast as they accumulate. However, without estrogen the rate of pothole formation increases, as in, the osteoclasts are more active, and the road crews (the osteoblasts) are no longer able to keep up.
The common medications for osteoporosis act by blocking the effects of estrogen deficiency, slowing down the osteoclasts, and thereby giving the osteoblasts a chance to keep pace with the osteoclasts. The goal is to get the process back to where it was before the woman’s menopause. Osteoclasts are still at work breaking down bones, but no longer at such a rapid rate.
HEALTH FOOD PRODUCTS HAVE NOT BEEN SHOWN TO WORK
Patients who already have osteoporosis frequently want to go to a health food store, hoping to pick up something off the shelf to alleviate their osteoporosis. However, the products available in health food stores, such as calcium or over-the-counter strontium supplements, have not been shown to decrease the risk of fracture for those who already have osteoporosis. There’s a superficial plausibility that they’d work because bones contain calcium and some individuals clearly don’t get enough calcium. However, while some calcium may be helpful, too much calcium has recently been associated with an increased risk for heart problems. There is a prescription form of strontium ranelate available in Europe, but it is not available in the U.S.,and the strontium available without a prescription in the U.S. is not identical.
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