Comparison of respiratory symptoms and pulmonary functions of adult male cigarette smokers and non-smokers in Sri Lanka; A comparative analytical study.

backgroundCigarette smoking has long been associated with decreased lung function and increased respiratory symptoms globally. While this relationship is well-established, a critical gap exists in our understanding of the specific impact of smoking intensity on individual lung volumes, particularly among the general population. Despite numerous studies conducted on this topic worldwide, there is a noticeable absence of research focusing on the Sri Lankan population, and South Asian studies in this context remain sparse. This study evaluated the prevalence of respiratory symptoms and pulmonary function changes among chronic cigarette smokers and compared them with non-smokers. Furthermore, the proposed study intends to close this gap by undertaking a systematic assessment of the influence of cigarette smoking on lung function and respiratory symptoms in the general population of Sri Lanka. Additionally, the present research represents the first-ever Lung function study conducted in Sri Lanka specifically targeting cigarette smokers.

methodsAdult male daily smokers (n = 360) and matched non-smokers (n = 180) from the Colombo district, Sri Lanka, were chosen. Smokers were compared in age, height, and weight with a matched nonsmoking control group. An interviewer provided a questionnaire to collect data on socio-demographic information, smoking behaviors, and clinical respiratory symptoms. Lung function tests were performed with a calibrated PC-based Medikro® Pro (Finland) spirometer and forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and FEV1/ FVC ratio, peak expiratory flow (PEF), forced expiratory flow between 25% and 75% of FVC (FEF 25-75%) were measured.

resultsSmokers had a significantly higher prevalence of respiratory symptoms and significantly lower FVC, FEV1, FEV1/ FVC, and PEF, FEF 25-75% values than non-smokers. There was a significantly negative correlation of FVC, FEV1, FEV1/ FVC, and PEF, FEF 25-75% with the duration of smoking, and the Brinkman Index. According to the Multiple regression analysis, smoking significantly contributed to deteriorated pulmonary function variables.

conclusionThis study revealed that continuous smoking accelerates the deterioration of lung function and increases respiratory symptoms. Early strategies to reduce tobacco use are recommended.