Saturday, March 30, 2013

Vitamin D Levels Tied to Lung Health

Serum vitamin D levels had a significant positive correlation with pulmonary function, most prominently in patients with a history of tuberculosis (TB), data from a large cross-sectional study showed.

In the subgroup of patients with a history of pulmonary tuberculosis, the absolute difference in FEV1 by 25-OHD level was four times greater than the difference in the overall population, they wrote in the Journal of Clinical Endocrinology & Metabolism.

"The precise mechanism for this phenomenon remains unknown, but it has been suggested that vitamin D accelerates recovery from infection by enhancing innate immunity via upregulation of antimicrobial peptides," they added.
Observational studies of vitamin D and respiratory function have yielded mixed results. Clinical trials of vitamin D supplements as prophylaxis against respiratory disease also failed to demonstrate a definitive association, the authors said.

Comparing the top and bottom quartiles of 25-OHD, the authors found a difference of 229 mL for FEV1 in the subgroup of participants with a history of pulmonary TB (P<0 .01="" p="">
The study had some limitations, namely that it was cross-sectional so reverse causality could not be ruled out. Also, the overall low 25-OHD levels in the participants limited the authors' ability to adequately estimate optimal vitamin D levels for lung function. Finally, data on sun exposure and dietary or supplementary vitamin D intake were not available.

To read the full article on Medpage Today, click here.