Because asthma is an inflammation of the airways in the lungs, most patients are prescribed anti-inflammatory medications. Oral corticosteroids, such as prednisone, are the most potent anti-inflammatory drugs used to treat asthma. They have a number of known side effects, one of which is bone loss that results in osteoporosis. This type of osteoporosis is known as steroid-induced osteoporosis, or glucocorticoid-induced osteoporosis.
Inhaled corticosteroids are highly effective anti-inflammatory agents that are significantly safer than those administered orally, because less of the drug in its active form is absorbed into the body. Nonetheless, higher doses of inhaled corticosteroid may still cause side effects, including osteoporosis. Therefore, your allergist will always use the lowest effective dose of oral corticosteroid, if it is required, and prescribe inhaled — rather than oral — medication whenever possible, again using the lowest dose that will control asthma symptoms.
If you need daily prednisone or a similar drug to control your asthma, your doctor may want to determine your bone density. Bone mineral density tests are recommended starting at age 65; if you use corticosteroids to control your asthma, you may need earlier monitoring. Your doctor will determine the frequency of bone mineral density monitoring. The test is similar to an X-ray, though with much less radiation.
Who gets osteoporosis?
An estimated 10 million people older than 50 have osteoporosis, and almost 34 million people have low bone mass that puts them at a higher risk for getting the disease. Older people, especially women who have reached menopause, are most at risk. Other factors that increase the risk of osteoporosis are:
- Family history
- Race (non-Hispanic Caucasians and Asians are at higher risk than African-Americans)
- Inadequate calcium and vitamin D intake
- Lack of physical activity
- Cigarette smoking
- Low body weight
- Gender (more common in women)
- Excessive use of alcohol
- Taking oral cortisonelike medications (glucocorticoids) or taking relatively high doses of inhaled corticosteroids
- Taking anti-seizure medications
- Estrogen deficiency in women; low testosterone levels in men
The most common sites for broken bones are the small bones of the back (vertebrae), wrists, upper arms, pelvis and hips. Patients who break one bone are at an increased risk for additional fractures. Broken bones can result in pain, loss of movement and the possible need for surgery.
Signs and symptoms of osteoporosis
In the early stages of osteoporosis, you may not experience pain or symptoms. Once the bones are weakened, symptoms may include:
- Back pain, which may be severe if there is a fracture or vertebrae are collapsed
- Loss of height and stooped posture
- Fracture of vertebrae, wrist, hip or other bones
Bone mass loss due to corticosteroid use occurs most quickly in the first three to six months; studies have shown a loss of up to 10 percent of bone mineral density in the first year, eventually settling down to a loss of 2 to 5 percent per year until the medication is stopped.
Strategies for preventing osteoporosis
You should be sure to get sufficient amounts of calcium. The Food and Nutrition Board at the Institute of Medicine of the National Academies has set these recommended dietary allowances for calcium:
- 1 to 3 years of age: 700 mg/day
- 4 to 8 years of age: 1,000 mg/day
- 9 to 13 years of age: 1,300 mg/day
- 14 to 18 years of age (including pregnant and lactating): 1,300 mg/day
- 19 to 50 years of age (including pregnant and lactating): 1,000 mg/day
- Men 51 to 70 years of age: 1,000 mg/day
- Women 51 to 70 years of age: 1,200 mg/day
- 71 years of age and older: 1,200 mg/day
Calcium is best absorbed if taken with meals in small amounts throughout the day. The most concentrated calcium sources are dairy products. If you are not able to drink milk, ask your doctor about other ways to increase your calcium intake.
You should also have your vitamin D levels checked. Vitamin D regulates the body’s absorption of calcium and can reduce bone resorption and subsequent bone loss. Many Americans are vitamin D-deficient and require supplements, which are sold over the counter.
Additional strategies for preventing osteoporosis are:
- Exercise. Weight-bearing and muscle-strengthening activity is especially helpful. The goal is to exercise every other day, or four times a week. The length of time depends on the intensity of the exercise. If you have been inactive, consult your doctor before you begin a new exercise regime.
- Examples of weight-bearing exercise are walking, hiking, climbing stairs, jogging, dancing and playing tennis.
- Examples of muscle-strengthening exercises are weight training and resistive exercises.
- Don’t smoke.
- Avoid consuming alcohol in excess.
- If you are a man taking oral corticosteroids, your doctor may recommend a blood test to make sure that your testosterone level is not low.