Correlation between amount of smoking and decline in lung function among urban male population

A cross sectional study of six months duration was conducted at the Department of Pulmonology, Shaikh Zayed Hospital, Lahore to compare the lung function decline [percentage of predicted forced expiratory volume in one second with amount of smoking in different groups of subjects according to pack years of smoking. Data was collected from four hundred current smokers meeting inclusion and exclusion criteria collected by arranging free spirometry camps by non-probability purposive sampling. The study participants were having ages between 20 and 67 years with mean age of 38.1 +/- 12.2. It was found that cases in group up to 5 pack years of smoking had highest average FEV[1] 98.0+/-5.3 and FEV[1] decreased smoothly as number of pack years escalated. It was 96.0+/- 10.9 in 6-10 pack year group, 90.0 +/- 9.8 in 11-15 pack years group, 85.3+/-7.2 in group 16-20 and it was 71.9 +/- 16.2 in group 21 and above pack years of smoking. In our study we also found that 79 [19.75%] participants had FEV[1] between 80-50% of predicted out these 58 [73.41%] were in group 21 and above pack years of smoking whereas 08 participants had FEV[1] less than 50% of predicted. It was concluded that the prevalence of undetected persistent airflow obstruction was high and more frequent in smokers having history more than 21 pack years of smoking