ABSTRACT:

Context: Much is known about ill effects of smoking and tobacco use, but little about the beneficial effects that follow cessation or reduction of smoking habit. Hence this study intends to explore the same.

Objectives:

To assess the improvement in pulmonary function after complete cessation or reduction of smoking.

To examine the effect of factors such as age and duration of smoking on such improvement, if any.

Design: Serial prospective study

Setting: Smoking Cessation Clinic, National Institute of Mental Health And Neurosciences (NIMHANS), Bangalore.

Subjects: 65 healthy adult smokers presenting voluntary to undergo de-addiction.

Outcome measures: FEV1, FVC, FEV1/FVC and PEF

Protocol: Baseline lung functions recorded and measured again at serial intervals of 4 weeks, till 12 weeks after onset of cessation program. Subjects grouped into quitters, modifiers and non quitters based on their response to the de-addiction program. Results statistically analyzed for significant differences in trend of above parameters.

Results: Following cessation or modification of smoking habit, a definite improvement in all the above lung function parameters was seen. In quitters, FEV1 increased by 382.14 mL (p<0.001), FVC increased by 333.21 mL (p<0.001), FEV1/FVC increased by 0.0412 (p<0.001) and PEF increased by 0.64 L/sec (p<0.001). In modifiers FEV1 increased by 162 mL (p<0.001), FVC increased by 202.66 mL (p<0.001), FEV1/FVC increased by 0.022 (p<0.01) and PEF increased by 0.29 L/sec (p<0.001). The same parameters did not show significant change in non-quitters. The improvement in quitters showed inverse relationship with age, BSA, and duration of smoking.

Conclusions: Cessation or significant reduction of smoking is followed by significant improvement in lung function. The improvement varied inversely with age and degree of exposure to smoking.

Abbreviations:

FEV1: Forced Expiratory Volume in first second

FVC: Forced Vital Capacity

PEFR: Peak Expiratory Flow Rate

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