Comparative analysis of pulmonary functions, inflammatory and oxidative stress biomarkers in smoker and biomass smoke exposed COPD

Introduction: Non-smoking chronic obstructive pulmonary disease (COPD) is one of the major contributors among total COPD cases in low- and middle-income countries. This study aimed to investigate pulmonary functions and estimate systemic and airway inflammatory and oxidative stress markers in serum and exhaled breath condensate (EBC) of cigarette-smoking COPD and biomass smoke-exposed COPD patients, comparing them with healthy smokers and healthy non-smokers. Methods: A total of 45 participants were enrolled: smoker COPD (n=10), biomass smoke-exposed COPD (n=10), smoker control (n=10), and non-smoker control (n=15). Pulmonary function tests, including spirometry and impulse oscillometry, were performed. Inflammatory and oxidative stress marker levels in both serum and EBC were estimated. Results: Spirometric parameters, including slow vital capacity (SVC), forced expiratory volume at 1st second (FEV1), forced vital capacity (FVC), and FEV1/FVC were significantly less in COPD groups (smoker/biomass) as compared to controls. Smoker COPD had less FEV1/FVC than biomass-exposed COPD. COPD groups (smoker/biomass) exhibited significant impairment in lung mechanics, characterized by increased peripheral airway resistance (R5-R20), reactance at 5 Hz (X5), and resonant frequency (Fres), indicating involvement of peripheral airways. However, no significant change in lung mechanics exists between smokers’ COPD and biomass-exposed COPD. Among the oxidative stress markers, 8-isoprostane and nitrotyrosine-3 (NT3) levels in EBC were significantly higher in smoker-COPD compared to biomass-exposed COPD and non-smoker controls, respectively. Conclusion: Significant pulmonary function impairment was observed in both smoker COPD and biomass smoke-exposed COPD. Inflammatory and oxidative stress markers are more deranged in smoker COPD than in biomass smoke-exposed COPD and healthy controls.