What People with Asthma Need to Know about Osteoporosis
Osteoporosis is a condition in which the bones become less dense and more likely to fracture. Fractures from osteoporosis can result in pain and disability.
The Connection Between Asthma
People with asthma tend to be at increased risk for osteoporosis, especially in the spine, for several reasons. First, anti-inflammatory medications, known as glucocorticoids, are commonly prescribed for asthma. When taken by mouth, these medications can decrease calcium absorbed from food, increase calcium lost from the kidneys, and decrease bone formation. Doses of more than 7.5 mg each day can cause significant bone loss, particularly during the first year of use. Corticosteroids also interfere with the production of sex hormones in both women and men, which can contribute to bone loss, and they can cause muscle weakness, which can increase the risk of falling and related fractures.
Many people with asthma think that milk and other dairy products trigger asthma attacks, although the evidence shows that this is only likely to be true if they also have a dairy allergy. This unnecessary avoidance of calcium-rich dairy products can be especially damaging for children with asthma who need calcium to build strong bones.
A well-balanced diet rich in calcium and vitamin D is important for healthy bones.
Because exercise often can trigger an asthma attack, many people with asthma avoid weight-bearing physical activities that are known to strengthen bone. Those people who remain physically active often choose swimming as their first exercise of choice because it is less likely than other activities to trigger an asthma attack. Unfortunately, swimming does not have the same beneficial effect on bone health as weight-bearing exercises, which work the body against gravity. Weight-bearing exercises include walking, jogging, racquet sports, basketball, volleyball, aerobics, dancing, and weight training.
Strategies to prevent and treat osteoporosis in people with asthma are not significantly different from those used to treat people who do not have asthma:
A well-balanced diet rich in calcium and vitamin D is important for healthy bones. Good sources of calcium include low-fat dairy products; dark green, leafy vegetables; and calcium-fortified foods and beverages. Supplements can help ensure that the calcium requirement is met each day, especially in those with a proven milk allergy. The Institute of Medicine recommends a daily calcium intake of 1,000 mg each day for men and women, increasing to 1,200 mg daily for those aged 50 and older.
Vitamin D plays an important role in calcium absorption and bone health. It is synthesized in the skin through exposure to sunlight. Food sources of vitamin D include egg yolks, saltwater fish, and liver. Many people obtain enough vitamin D by getting about 15 minutes of sunlight exposure each day or from eating fortified foods. Other individuals – especially those who are older or housebound, live in northern climates, or use sunscreen – may require vitamin D supplements to achieve the recommended intake of 400 to 600 IU each day.
Like muscle, bone is living tissue that responds to exercise by becoming stronger. The best kind of activity for your bones is weight-bearing exercise that forces you to work against gravity. Regular exercise may help prevent bone loss and provide many other health benefits. People who experience exercise-induced asthma should exercise in an environmentally controlled facility and participate in activities that fall within their limitations. They may also use medication when necessary to enable them to exercise.
Smoking is bad for bones, as well as the heart and lungs. Women who smoke tend to go through menopause earlier, triggering earlier bone loss. In addition, people who smoke may absorb less calcium from their diets. Alcohol also can affect bone health negatively. Those who drink heavily are more prone to bone loss and fracture because of both poor nutrition and an increased risk of falling.
Reducing exposure to asthma triggers can help lessen a person’s reliance on glucocorticoid medication. Avoiding people with colds and other respiratory infections and minimizing emotional stress can also be important.
Bone Density Test
A bone mineral density test measures bone density at various sites of the body. This test can detect osteoporosis before a fracture occurs and can predict one’s chances of future fracture. People with asthma, particularly those receiving glucocorticoid therapy for two months or more, should talk to their doctors about whether they might be candidates for a BMD test.
Like asthma, osteoporosis is a disease with no cure. However, there are medications available to prevent and treat osteoporosis. Because of their effectiveness in controlling asthma with fewer side effects, inhaled glucocorticoids are preferred to oral forms of the medication. Bone loss tends to increase with increased glucocorticoid doses and prolonged use; therefore, the lowest possible dose for the shortest period of time that controls asthma symptoms is recommended.
Source: National Institutes of Health
This article was originally published in Coping® with Allergies & Asthma magazine, July/August 2009.