Vitamin D supplementation in patients with asthma or chronic obstructive pulmonary disease (COPD) is associated with reduced molar ratios of 25-hydroxyvitamin D3 (25[OH]D3)-to-vitamin D3 and increased molar ratios of 1α,25-dihydroxyvitamin D3 (1α,25[OH]2D3) in serum, according to the results of a longitudinal study published in the American Journal of Respiratory and Critical Care Medicine.
Vitamin D deficiency is common in patients with asthma and COPD, and low 25(OH)D levels may represent a reversible cause or a consequence of these conditions. Thus, researchers sought to determine whether vitamin D metabolism differs between patients with asthma or COPD compared with control individuals. The investigators administered 6 oral doses of 3 mg vitamin D3 over 1 year in 186 adults (88 with asthma, 79 with COPD, and 19 control individuals).
The mean post-supplementation 25(OH)D level increase in participants with asthma (20.9 nmol/L) and COPD (21.5 nmol/L) was lower than in control individuals (39.8 nmol/L; P =0001). Patients with asthma and COPD had lower molar ratios of 25(OH)D3-to-vitamin D3 and higher molar ratios of 1α,25[OH]2D3-to-25(OH)D3 both pre- and post-supplementation (P ≤.005) compared with control individuals. However, intergroup differences in 1α,25[OH]2D3-inducible gene expression signatures were modest and variable where statistically significant.
“In conclusion, we report that the 25(OH)D response to vitamin D supplementation was attenuated in adults with asthma and COPD, as compared with controls with neither condition,” the researchers wrote. “This phenomenon was associated with reduced molar ratios of 25(OH)D3-to-vitamin D3 and increased molar ratios of 1α,25(OH)2D3-to-25(OH)D3 in the serum, suggesting that vitamin D metabolism is dysregulated in these conditions.”
Jolliffe DA, Stefanidis C, Wang Z, et al. Vitamin D metabolism is dysregulated in asthma and chronic obstructive pulmonary disease [published online March 18, 2020]. Am J Respir Crit Care Med. doi:10.1164/rccm.201909-1867OC