RESUMEN
BACKGROUND AND OBJECTIVE: Tobacco smoking is an established risk factor for chronic obstructive pulmonary disease (COPD). Current evidence suggests that non-tobacco-related risk factors vary geographically and are less understood than smoking. This study aims to compare the risk factors, symptoms, and clinical features of smoking (S-COPD) and non-smoking (NS-COPD) in a COPD population. MATERIALS AND METHODS: In this retrospective cross-sectional study, 489 COPD patients were screened. Data on socio-demographics, smoking and medical history, other risk factors, symptoms, and clinical characteristics including COPD Assessment Test (CAT) score, and Modified Medical Research Council (mMRC) Dyspnea Scale were examined. RESULTS: Of the total selected 416 COPD patients, 35.34% were NS-COPD while 64.66% were S-COPD. S-COPD was predominant in males, whereas NS-COPD was predominant in females (P < 0.0001). In NS-COPD, biomass fuel exposure was a major risk factor (P < 0.0001), and 61% of subjects had a biomass fuel exposure index of >60. In bivariate and multivariate analyses, no risk factors were correlated with forced expiratory volume in 1 second (FEV1)% predicted, while among clinical features, duration of illness (P = 0.001) was correlated with lower values of FEV1 in the multivariate table of S-COPD. In the multivariate analysis, biomass fuel exposure (P = 0.039) and CAT score (P < 0.0001) were correlated with FEV1(%) in NS-COPD. CONCLUSION: Biomass fuel exposure is a substantial risk factor for NS-COPD and was correlated with FEV1(%) predicted. In addition, the CAT score correlated with disease severity in patients with NS-COPD. The development of COPD in non-smokers is being recognized as a separate phenotype and it should be managed according to risk factors.