Comparison of forced expiratory volume in one second (FEV1) among asymptomatic smokers and non-smokers

Objective: To compare the forced expiratory volume in first second (FEV1) among asymptomatic smokers and non-smokers for evaluating the effect of cigarette smoking on healthy subjects. Methods: This was a Comparative cross-sectional study done at military hospital Rawalpindi from June 2006 till June 2007. Two hundred male subjects, 100 smokers and 100 non-smokers were included using non-probability convenience sampling. SCHILLER SPIROMETER (SP-1A) was used to measure forced expiratory volume in one second in all individuals. Best FEV1 was obtained after three efforts. Results: FEV1 was measured in a population of male smokers less than 45 years of age, and compared with a matched group of non smokers, mean age being 35.08 ± 4.73 years (n=200) and mean height of 170.73 ± 5.76 cm (n=200). The prevalence rates of previously undetected airflow obstruction were studied according to the British Thoracic Society (BTS) criteria. This study showed that 16 out of 100 smokers had mild airway obstruction while only 01 non smoker out of 100 had FEV1 levels below 80%. The prevalence rate of airway obstruction was associated with age and the number of pack years of smoking. Conclusion: The prevalence of undetected airflow obstruction is high among asymptomatic smokers. Targeted screening therefore, especially in smokers needs to be considered. Since lung function declines with time, therefore best time to prevent morbidity and mortality from smoking-related illness should be early in life.