Comparative Study of Lung Volumes and Capacities in Smokers and Non-Smokers of 5 Years Duration

Abstract

Background: Smoking is a common habit prevalent in both urban and rural areas of India. Cigarette smoking has extensive effects on respiratory function and is clearly implicated in the etiology of a number of respiratory diseases, particularly chronic bronchitis, emphysema, and bronchial carcinoma. An attempt has been made to study the pulmonary function tests among the smoking and non-smoking population in the urban area of Secunderabad, Telangana, South India.
 Objective: The primary objective of this research was to study the influence of smoking on pulmonary functions.
 Design: This was a cross-sectional study.
 Duration: One year i.e. from November 2014 to October 2015.
 Setting: Gandhi Hospital, Secunderabad, Telangana, South India.
 Participants: 80 patients attending the Medicine Out Patient Department, Gandhi Hospital.
 Methods: The study subjects were classified as smokers or non-smokers based on WHO suggested classification criteria. After recording detailed history, smoking index was calculated for smokers to evaluate dose-duration response relationship. Spirometry was performed to assess the pulmonary function of the subjects. The results are given as Mean ± Standard deviation and Standard error values. Comparison performed using student’s t-test for 2 groups. The P value of 0.05 or less was considered significant.
 Results: 57.5% of smokers were light smokers, 27.5% were moderate and 15% heavy smokers. FVC was significantly lower in smokers compared with non-smokers(p<0.05), Also this decrease was significantly higher as the no. of cigarettes smoked per day increased(p<0.05). FEF25-75% was also found to be significantly reduced in smokers compared with non-smokers. PEFR was significantly reduced in smokers and even this parameter showed a comparable fall(p<0.05) with intensity and duration of smoking. FEV1 also showed a significant decrease in smokers especially those with greater duration and amount of smoking (p<0.05). FEV1/FVC ratio showed a significant fall in smokers compared with non-smokers(p<0.05), but this fall was not so significant as the no. of cigarettes smoked per day increased(p>0.05), however like other indices FEV1/FVC showed a significant decrease(p<0.05) as the duration of smoking increased. 
 Conclusion: It may be concluded that smoking causes definite pulmonary function impairments, especially the obstructive type.
 Keywords: Lung Volumes, Lung Capacities, Comparision, Smokers, Non-Smokers.