THE EFFECTS OF SMOKING ON PULMONARY FUNCTION TESTS: A CROSS-SECTIONAL STUDY IN PAKISTAN

Abstract

The connection between smoking and pulmonary function tests remains partially undefined because additional scrutiny of smoking effects on these assessments is necessary.  The main goal of this investigation examined the smoking-related impact on adult measurements from spirometric and diffusion capacity examinations. Researchers utilized 250 participants under cross-sectional sampling (125 nonsmoking subjects and 125 smokers who accumulated five packs or more).  Participants underwent Peak Expiratory Flow and Forced Vital Capacity alongside Forced Expiratory Volume in One Second evaluation and the FEV₁/FVC proportion and Carbon Monoxide Diffusing Capacity measurement.  The statistical analysis used independent t-tests, Mann-Whitney U tests alongside multivariable regression adjusted for age, sex and BMI. Smoking resulted in significant decreases in mean FEV₁ (2.8 vs. 3.5 L, p<0.001) and FVC (3.6 vs. 4.2 L, p<0.001) together with DLCO (75% vs. 92% predicted, p<0.001) between smokers and non-smokers.  People who smoked cigarettes presented with a decreased ratio of FEV₁ to FVC measuring at 68% while participants who did not smoke maintained a ratio of 83% (p<0.001).  The relationship between PFT impairment and pack-year total showed a proportional association (β=-0.45, p<0.001 for FEV₁).  The research demonstrates how smoking reduces both gas exchange ability and restricts airflow while emphasizing the critical need for targeted smoking cessation programs.