Inhaled steroids, widely used to treat asthma, cause bone loss in young women, researchers report.
Anti-inflammatory steroids taken in pill form are known to accelerate bone loss, but it was not clear whether steroids inhaled directly into the lungs also thin bones.
Researchers at Boston's Brigham and Women's Hospital found a direct relation between the amount of inhaled steroids used and a decrease in bone density in the 109 women studied.
Bone loss can lead to osteoporosis.
"The importance of this is that we know there's an effect, and the message really is we need to use inhaled corticosteroids at the lowest doses that we can," said Dr. Elliot Israel, one of the researchers.
The findings are reported in today's New England Journal of Medicine. A second study in the journal shows that an osteoporosis drug prevents bone loss in men getting hormone therapy for prostate cancer.
The studies provide further evidence that some medications promote bone loss, said Dr. Bess Dawson-Hughes of Tufts University, who wrote an accompanying editorial.
"There are ways--medical, nutritional and otherwise--to prevent some, if not all, of this medical therapy-induced bone loss," she said.
The inhaled-steroid study looked at three groups of premenopausal women with asthma. One group did not use steroids to control the asthma. The two other groups used the same inhaled steroid, Azmacort, but at different doses.
Bone density was measured periodically over three years.
The researchers found small yearly decreases in bone density in the hip--but not the spine--in those who inhaled steroids. Those who used higher doses had more bone loss.
Israel said inhaled steroids are effective in treating asthma, and their use shouldn't be discouraged. But patients should try to use low doses, get sufficient calcium and vitamin D, exercise and have their bone density checked, he said.
Israel and his colleagues only studied women, but he said he would expect similar results in men who inhale steroids.
The second study was conducted at Boston's Massachusetts General Hospital and involved 47 men with advanced prostate cancer or a recurrence of the disease.
The study showed that the drug Aredia, also known as pamidronate, prevented bone loss associated with hormone therapy for prostate cancer, which decreases testosterone levels.
One of the researchers, Dr. Matthew R. Smith, said hormone therapy is an overlooked cause of osteoporosis in men, who account for 20% of the 10 million cases of the brittle-bone disease.