Early spirometric changes in asymptomatic smokers; is it a time dependent?

Abstract

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 nonsmokers. 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.

Relationship between concavity of the flow-volume loop and small airway measures in smokers with normal spirometry

“…Mid-expiratory flows have not yet been shown to be predictive of COPD. Part of the problem may be due to its high within- and between-individual variability, and its high prevalence of abnormality in smokers [ 14 , 15 ] most of whom do not develop COPD as currently defined by FEV/FVC. In contrast, imaging measures of small airways disease, lung clearance index, diffusing capacity for carbon monoxide, airway wall thickening and emphysema predict greater loss of FEV1 [ 16 , 17 ].…”

Assessment of the Effects of Cigarette Smoking on Lung Functions and Glucose Metabolism in Asymptomatic Current Cigarettes Smokers

“…The decreased pulmonary function tests (PFT) in smokers were established to be statistically significant for FEF 25-75% with no significant difference in other values. Mistry et al [14] they reported that at every age group, smokers had decreased FEV1/FVC ratio making them prone to develop COPD in the future. Nawafleh et al [15] and.…”