RESPIRATORY-FUNCTION TEST - DIFFERENCES BETWEEN SMOKERS AND NONSMOKERS - MODIFICATIONS AFTER SMOKING WITHDRAWAL

The purpose of this study is to determine the characteristics of spiro metric performance in a group of smokers and to carry out a prospectiv e study of the changes in ventilatory lung function after smoking with drawal. The ventilatory lung function was studied in 90 smokers and 30 non-smokers. Afterwards the smokers were included in smoking withdraw al program. One year later, the ventilatory function tests were repeat ed in those individuals who were able to stop smoking. Respiratory fun ction tests were likewise repeated in 10 subjects chosen randomly amon g those who were not able to stop smoking. The initial study of the ve ntilatory lung function showed that smokers had significantly lower va lues of FVC (p<0.001), FEV1 (p<0.001), FEVC1/FVC (p<0.001), FEF25-75 ( p<0.01 and PEF (p<0.01) compared to non-smokers. Likewise smokers also had a statistically significant higher prevalence rate of obstructive pulmonary disease (p<0.001). Ventilatory function studies performed o ne year after smoking withdrawal on those who were able to stop smokin g showed a significant improvement of respiratory function parameters compared to studies done one year before. There was also a significant decrease in the prevalence and severity of obstructive pulmonary dise ase. No differences were observed in the ventilatory function tests pe rformed on the ten subjects who did not stop smoking. From these data we suggest that tobacco consumption produces obstruction of the airway s that can be reverted, at least in part, after smoking withdrawal.