24:
Fixed Airways Obstruction In Smokers At 26 Years Of Age; An Early Indication Of COPD?
Saturday, March 3, 2018
South Hall A2 (Convention Center)
John W. Holloway, BSc PhD, Claire Hodgekiss, Graham Roberts, DM MSc MRCPCH, Wilfried Karmaus, MD, Hongmei Zhang, PhD, Susan Ewart, Linda S. Mansfield, VMD, PhD, Ramesh Jagath Kurukulaaratchy, BM DM MRCP, Syed H. Arshad, DM, FRCP
RATIONALE: It is not known how early lung function deficits occurs in smokers and when it shows signs of lack of reversibility, which would indicate risk of developing COPD.

METHODS: The IOWBC is a population based cohort (n=1456), recruited in 1989- 90 and assessed at birth, 1, 2, 4, 10, 18 and 26 years for asthma and allergic diseases and environmental exposures. Spirometric lung function tests were carried out using standardized methodology at 18 (n=839) and 26 years (n=555) before and after inhaled bronchodilator (salbutamol 500ug). Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC ratio and mid-expiratory flows (FEF25-75) at 26 years and changes in these indices between 18 and 26 were compared in those who were currently smoking at 26 years with those who had never smoked.

RESULTS: Pre-bronchodilator lung function values were not different between smokers and non-smokers. However, post-bronchodilator FEV1 was significantly reduced in smokers compared to non-smokers between 18 and 26 years (mean difference in liters: -0.15 vs. -0.02; p=0.004), resulting in significantly lower FEV1/FVC ratio at age 26 (0.77 vs. 0.81; p=0.01) in smokers. Mid-expiratory flows were also lower in smokers (3.98 vs. 4.43; p=0.001) at age 26.

CONCLUSIONS: There is evidence of airways obstruction in smokers with reduction in both small and large airways occurring in early twenties that is relatively irreversible to bronchodilator even at this early age. Identification of those who are highly sensitive to tobacco smoke should lead to strategies aiming to prevent long term lung damage.