Vitamin D Deficiency Linked to Lower Lung Function

BOSTONVitamin D deficiency was associated with lower lung function and more rapid lung function decline in smokers over 20 years in a recent study of elderly men published in the American Thoracic Societys American Journal of Respiratory and Critical Care Medicine (Am. J. Respir. Crit. Care Med. July 19, 2012). The study 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.

 We found that vitamin D sufficiency (defined as serum vitamin D levels of less than 20 ng/ml) had a protective effect on lung function and the rate of lung function decline in smokers," said lead author Nancy E. Lange, MD, MPH, of the Channing Laboratory, Brigham and Womens Hospital.

In the study, vitamin D levels were assessed at three different time points between 1984 and 2003, and lung function was assessed concurrently with spirometry (the measurement of breath). In vitamin D deficient subjects, for each 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. In longitudinal models, vitamin D deficiency worsened the effect of pack years of smoking on the decline in FEV1 over time.  There was no significant effect of vitamin D levels on lung function or lung function decline observed in the overall study cohort, which included both smokers and non-smokers. This suggests that vitamin D sufficiency may have a protective effect against the damaging effects of smoking on lung function.

Previous studies on vitamin D have shown it to improve bone health and increase cognitive function.