Lack of Vitamin D Affects Lung Function

(Ivanhoe Newswire) — Vitamin D deficiency was previously linked to severe asthma and chronic obstructive pulmonary disease (COPD), but a new study shows it also alters lung structure and function in young mice.

"The results of this study clearly demonstrate that vitamin D deficiency alters lung growth, resulting in lower lung volume and decrements in lung function," Graeme Zosky, Ph.D., a research fellow at the Telethon Institute for Child Health Research in Subiaco, Australia, was quoted as saying. "This is the first direct mechanistic evidence showing that vitamin D deficiency alters lung development, which may explain the association between obstructive lung disease and levels of vitamin D."

Researchers studied mice with vitamin D deficiency and evaluated lung responses of two-week-old mice and compared them to control mice without vitamin D deficiency to see the effects the deficiency may have cause in the growth, structure, or function of the lungs.

Lung volume and lung function were evaluated using a plethysmograph, an instrument used to measure the amount of air in the lung, and via forced oscillation, a technique used to measure the resistance to air flow in the lungs. Microscopic lung tissue samples were also evaluated to assess changes in lung structure.

"The aim of this study was to determine if vitamin D deficiency results in altered lung function and/or structure as a potential explanation for the association between vitamin D and chronic respiratory disease," Dr. Zosky, who is also an adjunct senior lecturer at the University of Western Australia’s Centre for Child Health Research, was quoted as saying. "Specifically, we aimed to determine if vitamin D deficiency has an influence on lung growth as indicated by a decrease in lung volume. We also wanted to determine if the deficiency alters the mechanical properties of the lung tissue due to changes in the structure of the lung."

The study showed that airway resistance was much higher while lung volume was significantly lower in vitamin D deficient mice compared to control mice. Examinations of specific tissue responses revealed model mice had reduced lung function. Lungs were also smaller in model mice, which Dr. Zosky said could have been caused by the deficiencies of the mother or of the offspring.

"Due to the nature of this study, we were not able to determine whether the differences in lung size and function we observed in the deficient offspring were the result of their own deficient status or as a consequence of developmental deficits that occurred in-utero due to the mother’s deficiency," Dr. Zosky said.

"For the first time, we have demonstrated a direct role for vitamin D in causing decreased lung function in the absence of known confounders such as physical inactivity, confirming the assertion by epidemiological studies that there is a relationship between vitamin D deficiency and lung function," Dr. Zosky explained. "The differences we observed in lung volume and lung mechanics, which were substantial and physiologically relevant, raise serious concerns regarding the increased prevalence of vitamin D deficiency in communities around the world. The results also raise concerns about the potential this deficiency may have on lung health, and in particular, the potential impact deficiency may have on the susceptibility to obstructive lung disease."

SOURCE: American Journal of Respiratory and Critical Care Medicine, published online January 28, 2011