A test of vitamin D benefits on respiratory health mediated through inflammatory markers

Abstract

Previous studies have shown that vitamin D has beneficial effects on respiratory health. The role of inflammation as a possible mediator between vitamin D and respiratory health is not well understood. We used National Health and Nutrition Examination Survey 2001Survey -2006 to examine the mediating effects of biomarkers of inflammation on associations between vitamin D and respiratory health. Vitamin D was measured by serum 25 hydroxy vitamin D test. Respiratory health was measured by self-reported respiratory symptoms and chronic obstructive pulmonary disease (COPD). Biomarkers included C-reactive protein (CRP), alkaline phosphatase (AP), and five leukocyte measures. Models controlled for season, age, sex, race/ethnicity, body mass index, and current and former smoking. Lower levels of vitamin D were significantly associated with respiratory symptoms (linear trend p < 0.01) and with COPD (linear trend p < 0.0002) after adjusting for covariates. Adding biomarkers to the models to test for mediation, the vitamin D effect on respiratory health was not a consequence of any single marker but was partially attenuated as a combined result of leukocytes, AP, and CRP. Vitamin D is beneficial to improve respiratory health. Its benefits do not appear to be mediated by any single biomarker examined in this study; rather, benefits of vitamin D may act broadly through multiple mediating mechanisms.

Vitamin D status is associated with muscle strength and quality of life in patients with COPD: a seasonal prospective observation study

“…Although the current study cannot provide information on respiratory function, disease severity or exacerbation frequency, we do report data on CRP concentrations similar to other stable COPD cohorts55 and which may be a possible mediating factor between vitamin D and respiratory function 52. In the current study, CRP did not differ significantly between the seasons and was not correlated with serum 25(OH)D concentration at either time point, a finding that confirms the findings of others 52.…”

Vitamin D Status and Gestational Diabetes: Effect of Smoking Status during Pregnancy

“…provided a potential explanation related to oxidative stress and inflammation, which was associated with the development of type 2 diabetes . Smokers have increased oxidative stress and inflammation and since it is thought that vitamin D may have antioxidant and anti‐inflammatory effects, vitamin D status may have a differential effect in smokers and non‐smokers. In a recent study of elderly subjects, the association between vitamin D deficiency and c‐reactive protein (a biomarker of systemic inflammation) was stronger in smokers compared to non‐smokers .…”

Outcomes of Vitamin D Supplementation in Adults Who are Deficient and Critically Ill: A Review of the Literature

“…48 In noncritically ill subjects, 25(OH)D deficiency has been associated with chronic obstructive pulmonary disease and respiratory symptoms. 50 In retrospective and prospective observational studies of ICU patients, 25(OH)D levels were inversely associated with mechanical ventilation days in medical ICU patients (10.04 6 1.97 days in vitamin D-deficient group vs. 3.15 6 0.15 days in vitamin D sufficient group, P 5 0.003) 45 and critically ill surgical patients (incident risk ratio per 10 ng/mL 5 0.66, 95% CI 5 0.39-0.66, P , 0.05) 48 ; however, in another study, there was no observed association between vitamin D deficiency and mechanical ventilation. 42 …”