Osteoporosis simply means weakening of bones: Osteopenia can be considered a mild, early phase of osteoporosis.
The most common cause of osteoporosis/osteopenia is vitamin D deficiency.
In addition, in postmenopausal women, loss of ovarian function at the time of menopause is another major reason for osteoporosis.
However, if a woman has surgical removal of her ovaries at a young age, she is susceptible to osteoporosis at a young age. Some women experience premature ovarian failure in their twenties or thirties. Consequently, these women are also at a high risk for the development of osteoporosis at a younger age.
Causes of Osteoporosis
1. Vitamin D deficiency
3. Spontaneous lack of menses for more than 6 months (pregnancy is an exception).
4. Low testosterone in men
5. Overactive thyroid gland
6. Overactive parathyroid glands (4 glands lying just posterior to the thyroid gland in the neck)
7. Certain gastrointestinal disorders
8. Certain drugs such as Prednisone, Dilantin and thyroid hormone in excessive doses.
9. Excessive calcium leakage from the kidneys, a rare condition.
Vitamin D Deficiency is the most common cause of osteoporosis in men and women. Unfortunately, Vitamin D deficiency remains undiagnosed in most people.
The main natural source of vitamin D is the sun. Fear of skin cancer and an indoor life-style has led to an epidemic of vitamin D deficiency. The situation is even worse in nursing home patients, patients with malabsorption syndrome and patients on certain medications such as Dilantin and steroids.
Menopause is another common cause for osteoporosis in women. Most women are already low in Vitamin D when they reach menopause. Then they get hit by estrogen deficiency: double whammy!
Low Testosterone in men, is a common cause of osteoporosis.
Other causes of osteoporosis for both men and women include:
If you are being treated for a thyroid disorder, it is very important to have a thyroid function test (a blood test) done on a regular basis. Your physician will recommend changes in the dose of thyroid hormone based on the thyroid function test.
Please note that in many patients with thyroid cancer, thyroid hormone is intentionally given in large doses to prevent the recurrence of the cancer. In such cases, measures taken to prevent or minimize bone loss should be discussed with the physician, preferably an endocrinologist.
Prolonged use of steroids, such as Prednisone, which if used in a daily dose of more than 7.5 mg for more than a few weeks, can cause significant bone loss.
Another common cause for osteoporosis is an Overactive parathyroid gland, which is usually discovered incidentally on routine blood testing, showing a high calcium level.
Wasting of Calcium in the urine (idiopathic renal calcium leak) is a rare condition that can cause osteoporosis.
Diagnosis of Osteoporosis
In the US, osteoporosis is most commonly diagnosed with the use of a widely available test called DEXA (dual energy x-ray absorptiometry) test.
It's important to note that the reliability of this test is dependent upon the technician. Interpretation of the test requires a physician knowledgeable in the field of osteoporosis, such as an endocrinologist, a rheumatologist or a radiologist.
Therefore, do your homework and use a reputable place before undergoing this test.
Bone density testing is available at most hospitals in the US.
Repeat testing in about 1-2 years should be done at the same place using the same machine in order to monitor the effects of therapy.
Who should have bone density testing done?
1. Anyone with untreated vitamin D deficiency.
2. Postmenopausal women.
3. Men with low testosterone
4. Anyone on Prednisone, Dilantin, or Excessive Thyroid Hormone.
5. Anyone with untreated overactive thyroid glands (hyperthyroidism).
6. Anyone with untreated overactive parathyroid gland.
7. Anyone with lack of menses for more than 6 months (except for pregnancy).
Do I need any more tests in addition to bone density testing?
Yes. The Bone density test can only diagnose whether or not you have osteoporosis. The next step is to find out the cause for osteoporosis.
Vitamin D deficiency is the most common cause for osteoporosis.
In most postmenopausal women, estrogen deficiency and Vitamin D deficiency are the main cause of osteoporosis.
Other causes of osteoporosis should also be investigated as many of these causes, such as overactive thyroid as well as parathyroid glands, are usually not clinically apparent.
Therefore, special laboratory tests need to be done to diagnose these conditions.
Osteoporosis in Men
Osteoporosis in men is usually discovered incidentally, such as the discovery of pathologic fractures (fractures with little on no trauma ) of the ribs, hip or spine on x-rays taken for some other reasons.
To determine the extent of bone loss, bone density measurement is carried out, usually by a bone DEXA test.
Appropriate testing should be done in order to determine the cause of osteoporosis, as treatment will depend upon the cause discovered in the individual patient.
Vitamin D deficiency and low testosterone are two major causes for osteoporosis in men
Treatment of Osteoporosis
Treatment of osteoporosis depends upon it's underlying cause. That's why it's important to determine the exact cause for osteoporosis.
In most patients with osteoporosis, vitamin D and calcium in appropriate doses are an important part of treatment.
In people who are on a long term steroid (such as Prednisone or Hydrocortisone) or Dilantin, vitamin D replacement becomes even more crucial.
Avoid excess thyroid hormone, unless it's done intentionally, as in patients with thyroid cancer.
Overactive thyroid disease such as Graves' disease should be appropriately treated by an endocrinologist.
For Primary Hyperparathyroidism, consider parathyroid surgery.
Drugs to Treat Osteoporosis
Drugs to treat osteoporosis in the U.S. are:
1. Fosamax (Alendronate)
2. Actonal (Risedronate)
3. Boniva (Ibandronate)
4. Evista (raloxifene)
6. Miacalcin (calcitonin) nasal spray
7. Estrogen Replacement Therapy, Testosterone replacement therapy in men who are low in testosterone.
8. Zoledronic acid (marketed under the trade names Zometa, Zomera, Aclasta and Reclast)
Fosamax, Actonel, Boniva and Zoledronic acid belong to the same class of drugs, known as bisphosphonate.
9. Prolia (Denosumab) is a recently approved anti-osteoporosis drug.
Each anti-osteoporosis drug has potential side-effects, which you should discuss with your physician before going on any of these drugs.
This article was written by Sarfraz Zaidi, MD, FACE. Dr. Zaidi specializes in Diabetes, Endocrinology and Metabolism.
Dr. Zaidi is a former assistant Clinical Professor of Medicine at UCLA and Director of the Jamila Diabetes and Endocrine Medical Center in Thousand Oaks, California.
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