Smoking is a major risk factor for COPD, which has been considered as a smoker’s disease. Dispelling this myth, COPD among non-smokers is now known to comprise one-third of all COPD patients globally. According to a new systematic review published online May 19, 2023 in the journal Respiratory Medicine, women and older adults are more likely to have non-smoking COPD.¹

A team of researchers from Spain conducted a systematic review of literature to describe COPD among people who had never smoked through a search of Embase and PubMed databases. Studies of patients who self-reported COPD based on their symptoms or defined COPD according to the pre-bronchodilator FEV1/FVC ratio values were not included in the review. Never-smokers included those who had never smoked or if they had smoked, the number of cigarettes was <100 in their lifetime or <1 cigarette daily in the preceding 6 months. The final analysis included 17 clinical trials.

A total of 57,146 subjects were included in the analysis. Of these, 25,047 were never smokers. Among the never-smokers, 2655 had non-smoking COPD. Analysis of data showed that COPD among the non-smoking population was more common among women and older adults. They also had higher preponderance of comorbidities.

This study shows the differences in COPD between never smokers and smokers. The high prevalence among women, especially in low- and middle-income countries, may be due to high exposure to indoor pollution due to biomass fuel. However, this review also brought out the lack of adequate evidence specifically regarding non-smoking COPD as just two of the 17 studies included in the analysis had an exclusive never-smoker study population. Given that non-smoking COPD accounts for at least one-third of all COPD patients, there is an urgent need for further research to better comprehend the natural history as well as clinical features of the disease in this patient group compared to that in the ever-smokers.

Reference

1. Carlota Rodríguez García, et al. Clinical characteristics of chronic obstructive pulmonary disease in never-smokers: A systematic review. Respir Med. 2023 Aug;214:107284. doi: 10.1016/j.rmed.2023.107284.