Background: Chronic obstructive pulmonary disease (COPD) is a progressive airflow limitation and decline in lung function. Although tobacco smoke is the leading risk factor for COPD, air contamination by wood-burning smoke is also of great concern. About half of the world's populations, especially in developing countries such as Iran, exploit this energy source for cooking and heating. It is remained unknown if COPD induced by wood smoke from baking bread (COPD-B) and COPD induced by tobacco smoke (COPD-S) have different symptoms and clinical presentations. To fill this gap, the present study was to describe such differences.
Materials and Methods: This retrospective cohort study was performed in Afshar COPD clinics affiliated with the Shahid Sadoughi University of Medical Sciences, Yazd, Iran. The clinical records of 231 patients with the COPD diagnosis were reviewed. After considering inclusion and exclusion criteria, 91 patients (46 with COPD-B and 45 with COPD-S) underwent physical examination and para-clinical assessments (i.e., respiratory function tests, Chest X-ray, and quality of life test).
Results: The COPD-B patients were mainly women at older age and had higher FEV₁/FVC and FEF-75; however, they had fewer post-bronchodilator positive responses to FEV₁ (suggesting a restriction pattern) and sputum production, compared to the COPD-S patients. Regarding the other parameters, there were no statistically significant differences between the two groups.
Conclusion: This was the first study evaluating and revealing some differences in the clinical and paraclinical characteristics of the COPD-B patients (with prolonged exposure to wood smoke from bread baking; >100 hours per year, for at least 10 years) and COPD-S patients (>10 packs per year of exposure to tobacco smoke).