Inhaled vitamin D supplementation rather than oral delivery could potentially improve lung function and reduce exacerbation in people with chronic lung diseases and should be explored in human-centered clinical trials, according to a new perspective in the May 2026 issue of Chronic Obstructive Pulmonary Diseases: Journal of the COPD Foundation, a peer-reviewed, open access journal.
Chronic obstructive pulmonary disease (COPD), which includes emphysema and chronic bronchitis, affects more than 30 million Americans and is the fourth leading cause of death worldwide. People with COPD and other chronic lung diseases typically have low vitamin D levels. These low vitamin D levels can lead to increased exacerbations and worse lung function.
While previous studies have examined oral vitamin D supplements as a potential treatment for chronic lung diseases, results show that improving vitamin D levels in the blood does not impact the lungs.
"Oral vitamin D is potentially inactivated by an enzyme in the lung's blood vessels, preventing it from reaching the airways," said Kevin D. Schichlein, Ph.D., of the University of North Carolina at Chapel Hill and lead author of the perspective. "We think direct delivery to the lungs could be a more effective option."
Research using cell and animal models suggests that inhaled or nebulized vitamin D can protect against dust, pollution, and pathogens. However, no clinical trials have explored whether inhaled vitamin D supplementation has the same impact in people with chronic lung disease.
"Low vitamin D levels are common among people with chronic lung disease, but the evidence shows that simply raising vitamin D levels in the blood does not translate into better outcomes in the lungs," said Ilona Jaspers, Ph.D., of the University of North Carolina at Chapel Hill and perspective author. "Future research should focus on evaluating inhaled vitamin D therapies in human clinical trials to determine whether direct lung delivery would deliver therapeutic benefits for people with chronic lung diseases."
To access current and past issues of Chronic Obstructive Pulmonary Diseases: Journal of the COPD Foundation, visit journal.copdfoundation.org .
