Chronic obstructive pulmonary disease, or COPD, includes a number of lung conditions, including emphysema and chronic bronchitis. Nearly all COPD deaths are due to a sudden worsening of symptoms (lung attacks), often triggered by viral upper respiratory infections, the researchers explained.
"New treatments are urgently needed to prevent COPD attacks. Our study shows that giving supplements to vitamin D-deficient COPD patients nearly halves their rate of potentially fatal attacks," said lead researcher Adrian Martineau, a professor at Queen Mary University of London.
In the study, Martineau and his colleagues analyzed data from 469 COPD patients from three clinical trials, which took place in the United Kingdom, Belgium and the Netherlands.
Taking vitamin D supplements was associated with a 45 percent reduction in lung attacks among patients who were deficient in vitamin D, but there was no reduction among patients with higher vitamin D levels, the investigators found.
The study was published Jan. 10 in the journal Thorax.
Vitamin D supplementation is safe and inexpensive, Martineau noted. "So this is a potentially highly cost-effective treatment that could be targeted at those who have low vitamin D levels following routine testing," he said in a university news release.
"Around a fifth of COPD patients in the U.K. -- about 240,000 people -- have low levels of vitamin D," Martineau added.
Worldwide, more than 170 million people have COPD, and the disease caused an estimated 3.2 million deaths in 2015.
The researchers pointed out that since the data in their study came from just three trials, the findings should be interpreted with a degree of caution.
Previous research from Queen Mary University found that vitamin D helps protect against colds, flu and asthma attacks.