Relation between vitamin d deficiency and severity of chronic obstructive pulmonary disease-a case control study

Introduction: Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disorder characterized by irreversible and progressive limitation of expirator y airflow. COPD is now considered as a systemic disease with several extra-pulmonary manifestations which include osteoporosis, muscle weakness, arrhythmia, stroke, cancer etc. The role of vitamin D in skeletal integrity is well established. Role of it in several other diseases like autoimmune, infectious, respiratory and cardiovascular diseases has been increasingly recognised. Data on vitamin D status in COPD in Indian population was limited while those comparing vitamin D with stage, pack year and body mass index were lacking.Aim: To assess Vitamin D in subjects with COPD and matched controls and also to study the variability in serum vitamin D levels with COPD disease characteristics. Materials and Methods: A total of 162 patients aged 18-65 years from south India presenting to kasturba hospital were included in the study. Serum 25- hydroxy-vitamin D were measured in 81 COPD patients (combined COPD stage A-D) and compared with 81 age and gender matched controls. Level < 20 ng/ml defined deficiency. Risk estimate with Odds ratio and association of COPD characteristics with Vitamin D was assessed using logistic regression analysis. Results: COPD patients had an increased risk for vitamin D deficiency compared to controls after adjustment for age and gender(OR =2.687 (1.40,5.13)). Variables associated with lower 25(OH) D levels in COPD patients were higher pack year (p=0.001), current smoking status (p=0.026), Low BMI (p=0.02), and GOLD stage III- IV (p=0.001). Conclusion: COPD was associated with an increased risk of vitamin D deficiency, and there was a significant association between vitamin D levels and Combined COPD stage severity. Also, a higher pack year and a low BMI are associated with lower levels of vitamin D.