Spirometry is the most widely used lung function test both in the diagnosis and stratification of severity of lung disease. The Forced Expiratory Flow between 25 and 75% of the FVC (FEF25_75) is one of the most commonly cited measures of small airways pathology.
This study aimed at evaluation of early effect of smoking on small airways.
It included: 50 asymptomatic smokers (Group 1) and 50 non smokers (Group 2) as a control.
The result revealed:
The subjects age was ranged from 18 to 75 years with mean age 43.12 ± 13.231SD in smokers, and range from 15-62 with mean age 41.74 years with ± 14.512SD in non-smokers. 62 % of the a symptomatic smokers were Manual workers which are the majority of the smokers, and 38 % for Mental worker while the majority of non-smokers were Mental worker 64 %, with 36 % for Manual worker. Smoking cigarette was most common (54 %), then marijuana (46 %).
The mean values of all the pulmonary function tests are significantly reduced in smokers compared to non smokers, although, they are within the normal range. The association of impaired PFTs in smokers was found to be statistically highly significant to FEF 25-75 (small airway). Otherwise; there were no significance to other values applying unpaired T test.
The most affected age group in significant FEF25-75 reduction was found in 36-55years old, females were more affected than males. The duration of smoking was the most independent risk factor that affects the small airways, than the type of smoking and number of cigarettes or stones per day.