PROSPECTIVE-STUDY ON THE EFFECT OF SMOKING AND NICOTINE SUBSTITUTION ON LEUKOCYTE BLOOD COUNTS AND RELATION BETWEEN BLOOD LEUKOCYTES AND LUNG-FUNCTION

Background-The influence of smoking and of nicotine substitution on th e counts of total blood leucocytes and leucocyte subsets and the relat ions between the counts and lung function was investigated. Methods-Th e study was a combined cross sectional and prospective study of 298 sm okers and 136 non-smokers. Forced expiratory volume in one second (FEV ,) was measured in all participants at baseline and six months after q uitting smoking in 160 ex-smokers (quitters) and 138 persons with smok ing relapse. Blood samples were obtained from all participants at base line and from 160 quitters and 30 continuing smokers two, six, 12, and 26 weeks after smoking cessation and from 92 quitters one year after the cessation of smoking. Results-Blood leucocyte counts and leucocyte subsets were all higher in smokers than in non-smokers. In cigarette smokers total leucocyte, neutrophil, and lymphocyte blood counts showe d a dose dependent relationship with the daily cigarette consumption a nd pack years consumption. In smokers the neutrophil blood count was i ndependently associated negatively with FEV, residuals. After quitting smoking total leucocyte, neutrophil, and lymphocyte blood counts decr eased during the first 26 weeks and after one year lymphocyte blood co unts were higher than in non-smokers. In quitters substituted with nic otine chewing gum (2 mg) the accumulated number of pieces of chewing g um used in the 12 weeks had an inverse relationship with the decrease in the total lymphocyte blood count at 12 weeks after smoking cessatio n. Conclusions-Leucocyte blood counts are raised in smokers and decrea se after smoking cessation. Neutrophil blood counts had an inverse rel ationship with lung function and nicotine may increase lymphocyte bloo d counts in smokers.