Lung Function and Respiratory Symptoms as Factors Associated with Smoking Cessation Status in a Population-Based Study

Background/Objectives: The aim of this study was to test the association of poorer spirometry and more respiratory symptoms with being an ex-smoker in a cohort of ever-smokers in a population-based study in Kazakhstan.

Methods

We first enrolled 5058 subjects, of whom 1769 were classified as ever-smokers (63% current and 37% former smokers) from the general population in five cities in Kazakhstan and analyzed them hereinafter. They filled in a questionnaire and underwent spirometry with bronchodilation, in which z-scores of post-bronchodilation forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were analyzed. Respiratory symptoms and spirometry were compared between continuing smokers and those who stopped in multivariate logistic regression models.