Vitamin D could help protect lungs in smokers

by Bruce Sylvester – Results from a new study suggest that Vitamin D deficiency is related to lung function in smokers, suggesting that vitamin D supplementation could be protective against of smoking on lung function.

“We examined the relationship between vitamin D deficiency, smoking, lung function, and the rate of lung function decline over a 20 year period in a cohort of 626 adult white men from the Normative Aging Study,” said lead author Nancy E. Lange, MD, MPH, of the Channing Laboratory, Brigham and Women’s Hospital, Boston Massachusetts. “We found that vitamin D sufficiency [defined as serum vitamin D levels of >20 ng/ml] had a protective effect on lung function and the rate of lung function decline in smokers.”

The findings were published online on July 20, 2012 ahead of print publication in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

The investigators evaluated vitamin D levels at three times between 1984 and 2003. They assessed lung function concurrently with spirometry.

They found that, in vitamin D deficient subjects, for each one unit increase in pack-years of smoking mean forced expiratory volume in one second (FEV1) was 12 ml lower, compared with a mean reduction of 6.5 ml among subjects who were not vitamin D deficient.

Using longitudinal models, they found that, over time, vitamin D deficiency worsened the effect of pack years of smoking on decline in FEV1.

They found no significant effect of vitamin D levels on lung function or lung function decline in the overall study cohort, which included both smokers and non-smokers.

“Our results suggest that vitamin D might modify the damaging effects of smoking on lung function,” said Dr. Lange. “These effects might be due to vitamin D’s anti-inflammatory and anti-oxidant properties.”

The authors emphasized that the study has limitations. The data was observational only, vitamin D levels fluctuate over time, and the study population was all elderly men.

“If these results can be replicated in other studies, they could be of great public health importance,” said Dr. Lange. “Future research should also examine whether vitamin D protects against lung damage from other sources, such as air pollution.”

“While these results are intriguing, the health hazards associated with smoking far outweigh any protective effect that vitamin D may have on lung function ,” said Alexander C. White MS, MD, chair of the American Thoracic Society’s Tobacco Action Committee. “First and foremost, patients who smoke should be fully informed about the health consequences of smoking and in addition be given all possible assistance to help them quit smoking.”