Osteoporosis and Parathyroid Disease
How Calcium Effects Osteoporosis and Parathyroid Disease
This page is about osteoporosis associated with parathyroid disease. If you simply want to lean about osteoporosis, then click here to go to our Osteoporosis Center.
How Does Our Body Regulate Calcium?
Calcium levels are regulated by the parathyroid glands. That's all the parathyroid glands do! Through the secretion of parathyroid hormone (PTH), these four small glands regulate how much calcium is absorbed from our diet, how much calcium is secreted by our kidneys, and how much calcium is stored in our bones. We store many pounds of calcium in our bones, and it is readily available to the rest of the body at the request of the parathyroid glands. When one of the parathyroid glands is overactive (hyperparathyroidism) the parathyroid tumor makes too much PTH hormone which then causes our bones to release calcium constantly into the blood stream. This causes the bones to lose their density and hardness (it is the calcium that makes them hard). Loss of calcium from bones is called osteoporosis. Bones which are osteoporotic are more likely to break! This picture shows a normal bone section on the bottom and a bone with osteoporosis on the top. The osteoporotic bone has bigger holes in it as a result of the calcium being dissolved and put into the blood stream (caused by excess parathyroid hormone, advanced age, and lack of estrogen in older females). The osteoporotic bone is not as strong and therefore, more susceptible to fractures. This continued dissolving of the central bone is what causes the bone pain so common to hyperparathyroidism. It is also what contributes to the weakening of the spinal column resulting in elderly persons walking "hunched over."
Our bones are at their strongest in our early 20s. They stay at this level of strength for a number of years, but then begin to lose strength slowly when we are in our mid 30s. Once we hit mid-life, we all lose a little bone density, but this is most evident for women. Estrogens have a protective effect on bone density which becomes evident after menopause when women begin to lose calcium from their bones at a faster rate then men of the same age. That is one of the reasons most doctors feel that most post-menopausal women should be on some form of estrogen therapy.
Now the problem becomes apparent. Overactive parathyroid glands secrete too much parathyroid hormone. This causes calcium to leave the bones and go into the blood. The bones become osteoporotic and prone to fractures. The problem is amplified greatly in post-menopausal women since this process is ongoing already! This can also a big problem for people of all ages if it goes on for several years, making the bones weaker year after year.
Will Fixing the Overactive Parathyroid Gland Help the Osteoporosis ?
YES! It has been known for many years that removing the bad parathyroid gland (or glands) (and the excess parathyroid hormone it produces) will stop the rapid and continuous loss of bone density. What was not known was whether the body would try to restore the calcium levels in the bones. Several recent studies have shown that the body will restore bone density after the excess hormone is removed. Researchers at the University of Northern Sweden studied the bone density of 12 postmenopausal women (average age 63) with primary hyperparathyroidism before and one year after parathyroidectomy [Thorsen, et al, Surgery 1997;122:882-7]. They found a significant increase in bone density in the hip and lower back one year later. This is a very slow process, and the bones will take many years to repair themselves, it does not happen overnight. In fact, depending on how much bone density has been lost, they may never regain their "normal" calcium levels and overall density. But at least we know that parathyroidectomy doesn't just stop the rapid loss of bone density, it allows the body to begin healing itself.
Can I Do Anything to Increase Bone Density ?
This is written for patients with hyperparathyroidism. And the answer used to be "nobody knows for sure, but we think so"....but now we can absolutely say YES!! All experts are now recommending that most patients take supplemental calcium after an operation to cure their hyperparathyroidism. Dr. Norman actually gives every patient a box of calcium and starts them on it within a couple hours of the operation. How long should you take calcium after your parathyroid operation?? It depends on your age, sex, menopausal status, and if you have a documented loss of bone density. The following list reflects most endocrinologist's and endocrine surgeon's overall recommendations regarding who should take supplemental calcium, but it is NOT written in stone, and your doctor may feel differently. Always follow your doctor's advice.
- Post-menopausal women
- Anyone with a bone density more than 1 standard deviation below their age-matched peers
- Most patients over the age of 60, male or female
- Young women who are thinking of having children (once pregnant, this MUST be under the care of the obstetrician).
There are some new drugs available which MAY help increase bone density even faster. These drugs are specifically designed to make bones add calcium to their structure. They have not been studied scientifically in the setting of hyperparathyroidism, but they may be a good idea AFTER the parathyroid tumor has been removed. Fosamax, Actonel, Evista, and Micalcin do NOT work if you have hyperparathyroidism. If you get the parathyroid tumor removed then these drugs may be very beneficial. In summary, everyone with parathyroid disease will get osteoporosis. The longer they have a parathyroid tumor, the worse the osteoporosis will be. There are ZERO drugs that can help reverse or slow the progression of osteoporosis if you have a parathyroid tumor. Once the parathyroid tumor is out your osteoporosis will get better, typically the increase in bone density is dramatic. In most patients the osteoporosis due to hyperparathyroidism is completely reversible.