(CBS) Many patients with chronic obstructive pulmonary disease (COPD), one of the most common lung diseases, have vitamin D deficiency. But a new study shows that high doses of vitamin D won't help.
COPD, also known as "chronic bronchitis" or "emphysema," impairs the movement of air in and out of lungs, causing shortness of breath. The disease usually gets worse over time, causing acute events known as "exacerbations." Patients with severe COPD tend to have low blood levels of vitamin D.
For the study - published in the Jan. 17 edition of the Annals of Internal Medicine - researchers in Belgium tested 182 COPD patients with a history of exacerbations. The researchers measured blood levels of vitamin D in patients, as they were given either vitamin D or placebo pills once per month for one year.
What did they find?
There was no difference in the number of exacerbations of COPD in patients who had received vitamin D pills and those who had not - even though the former did have increased levels of vitamin D.
Still, vitamin D is important for more than just hopes of preventing COPD exacerbations. "Be aware that vitamin D deficiency is prevalent in COPD and that it needs supplementation for bone health reasons," said study author Dr. Wim Janssens of University Hospital Gasthuisberg in Lueven.
But as far as easing symptoms of the lung disease, "Unfortunately, the results have been somewhat disappointing," Dr. Ken Kunisaki of the Minneapolis VA Healthcare System, told Reuters Health. "Right now there's no evidence that patients with COPD are going to benefit from additional vitamin D."
COPD is the third leading cause of death in the U.S. More than 12 million people are currently diagnosed with the disease, and an estimated 12 million may have COPD but not realize it.