Importance of smoking index for assessing lung damage by lung function tests

A total of 89 smokers of age varying between 15-52 years were assessed for lung function forced vital capacity (FVC), forced expiratory volume in one second (FEV1) ratio of FEV1 and FVC as FEV1% and peak expiratory flow rate (PEFR), before smoking (BS) and 30 min after smoking (AS). All the above lung function tests were reduced in smokers in comparison to those of age-matched non-smokers. Further, when observed test values of lung function were tabulated according to smoking index (SI), it was noted that reduction of lung function increased with SI.