A new study published in Respiratory Medicine has found another link between vitamin D and chronic obstructive pulmonary disease (COPD).
COPD is a disease most often caused from lifelong cigarette smoking and characterized by difficulty breathing. COPD includes two main conditions, emphysema and chronic bronchitis. In emphysema, the air sacs of the lungs are damaged. Chronic bronchitis, on the other hand, is characterized by irritated and inflamed lining of airways.
People with COPD usually have both emphysema and chronic bronchitis. While there has been much research in the past on the link between vitamin D and COPD, little research has looked at the emphysema aspect specifically. In the present study, researchers honed in on the emphysema aspect of the condition, making the study a first of its kind.
Researchers gathered data from 498 participants enrolled in the Evaluation of COPD Longitudinally to Identify Surrogate Endpoints (ECLIPSE) study. Of these participants, some were part of a smoker control group, a non-smoker control group, and some had moderate to severe COPD. The patients with COPD were further divided into groups of high and low emphysema levels.
In general, they found that a high percentage of participants across all groups had low vitamin D levels. Sixty-nine percent of patients were vitamin D insufficient or deficient (<30 ng/mL) and 39% were deficient (<20 ng/mL).
When they looked at vitamin D levels and how they correlated with emphysema, they found that lower vitamin D levels correlated with worse emphysema. They also found that vitamin D levels correlated with six-minute walk, bronchodilator response, and Clara cell secretory protein, the better the vitamin D level, the better the marker.
However, the researchers do caution that this may simply be correlation and not causation. Diet and decreased outdoor activity might affect vitamin D levels, and thus the association could’ve been triggered by reverse causality.
Further research should be able to clarify whether vitamin D can help in COPD. There have been some studies that show in COPD patients with severe vitamin D deficiency, vitamin D supplementation can help. Researchers will look to continue to further understand the relationship between vitamin D deficiency and COPD.
Berg, I. et al. Vitamin D, Vitamin D Binding Protein, Lung Function and Structure in COPD. Respiratory Medicine, 2013.