NEW YORK – In a new study of people with moderate or severe lung disease, taking large amounts of vitamin D was not linked to any symptom relief, researchers from Belgium report.

Prior research suggested that up to three quarters of people with severe chronic obstructive pulmonary disease, or COPD, are deficient in the vitamin. So it was thought that giving them extra vitamin D might help prevent exacerbations in symptoms or trips to the hospital because of shortness of breath or mucus in the airways — but that turned out not to be the case.

“Supplementation with vitamin D is not going to cure their disease,” said Dr. Wim Janssens, one of the study’s authors from University Hospitals Leuven.

“It is again clear for COPD patients that these exacerbations are really hard to treat” and prevent, Janssens told Reuters Health. “There are a lot of relapses. We’re basically failing in treating these.” Though vitamin D is most often associated with bone health and osteoporosis, Janssens said the theory has been that the vitamin may help reduce inflammation, including inflammation in the airways that worsens COPD symptoms, such as coughing and trouble breathing.

COPD is irreversible impairment of lung function, including emphysema and chronic bronchitis, often caused by smoking. One large national health survey suggests some 24 million Americans have the condition, according to the Centers for Disease Control and Prevention.

Janssens and his colleagues randomly assigned 182 people at their hospital with moderate to severe forms of the disease to take high-dose vitamin D pills, or a vitamin-free placebo pill, every four weeks for a year.