Abstract
Objective: To compare peak expiratory flow rates amongst smokers and nonsmokers.
Methods: This cross sectional study was carried out at 1 Mountain Medical Battalion and PAF Hospital Rafiqui from January to March 2014. Healthy male adults accompanying patients were selected by non-probability convenience sampling after verbal consent. Exclusion criteria included females, asthmatics, respiratory tract infections or patients unable to comprehend the technique of using peak flow meter. Hand held Mini-Wright peak flow meter was used to measure peak expiratory flow rate (PEFR) in a standing position. Best of three attempts was recorded. Height, weight and chest circumference were measured. History of smoking was obtained and quantified in terms of pack years.
Results: 376 individuals were stratified into three groups: group 1 (18-26 years) having 116 individuals including 29 (25.00%) smokers; group 2 (27-34 years), having 147 individuals including 56 (38.10%) smokers; and, group 3 (35 years or older) with 113 individuals including 44 (38.94%) smokers. Smokers in group 1 had a 4.19% lower PEFR than nonsmokers (P=0.077). Smokers in group 2 and 3 had PEFRs 7.83% and 15.50% lower than those of nonsmokers respectively (P<0.001). Smokers had much lesser PEFR than predicted values as compared to nonsmokers (P<0.05 for all age groups). Smoking load increased with age. There was a significant negative correlation between the number of pack years and PEFR (R= -0.359; p<0.001).
Conclusion: Smokers have lower peak expiratory flow rates as compared to nonsmokers, the difference being directly related to the amount of smoking.

Key words: smoking, peak expiratory flow rate, peak flow meter, respiratory function tests