Longitudinal Relation between Smoking and White Blood Cells

Abstract

Higher white blood cell counts in smokers compared with nonsmokers have been well documented, but the longitudinal relation between changes in smoking and changes in white blood cells has not been well described. Since 1984, data have been collected semiannually by the Multicenter AIDS Cohort Study (MACS), a four-center prospective cohort study of acquired immunodeficiency syndrome (AIDS) in homosexual men. The study population includes 2,435 participants who were human immunodeficiency virus (HIV) seronegative as of September 1994 and who contributed 20,918 person-visits for this analysis. For individuals who modified their smoking behavior, changes in white blood cell counts occurred primarily during the first 6 months following changes in the amount of cigarettes smoked. Among former smokers who resumed smoking, the extent of the increase in white blood cell count depended on the number of cigarettes smoked. Specifically, increases of 241, 340, and 740 cells/microliter were observed for smokers who resumed smoking < 1, 1 to < 2, and > or = 2 packs/day, respectively. Conversely, smokers who quit smoking had a decrease of white blood cell count: -32, -629, and -1,122 cells/microliter for men who previously smoked < 1, 1 to < 2, and > or = 2 packs/day, respectively. Long-term ex-smokers, however, still had higher white blood cell counts than did never smokers. There was a high within-individual correlation of white blood cell count in persons who reported a consistent level of smoking (i.e., average correlations between two white blood cell counts 6 years apart were 0.51 for never smokers, 0.48 for ex-smokers, 0.56 for men who smoked < 1 pack/day, and 0.43 for men who smoked > or = 1 pack/day). These analyses indicate an acute effect of changes in smoking on changes in white blood cell count, a residual effect of having been a smoker, and high long-term tracking for white blood cell count.

Effect of Chewing Tobacco on Hematological Parameters in Bikaner City Population

“…Thus it may be speculated that smoking or using other tobacco products may result in similar lowering of lymphocyte percentage. An earlier study had concluded that lymphocytes, especially cytotoxic T cells or CD8+ T cells may get lowered in smokers 25 . Variations in these T lymphocytes may make the smokers vulnerable to develop neoplastic growths and infections 26 .…”

White blood-cell count and the risk of impaired fasting glucose or Type II diabetes in middle-aged Japanese men

“…Because cigarette smoking had a strong impact on the risk for developing IFG or Type II diabetes in this study (incident rate of IFG or Type II diabetes mellitus among men with a WBC count of 2.5±5.2´10 9 cells/l: 8.2 per 1000 person-years for non-smokers and 17.2 per 1000 person-years for current smokers), the influence of WBC count on development of IFG or Type II diabetes mellitus might be obscured by cigarette smoking. As for the association of past smoking with WBC count, WBC count is related to the amount of time passed since quitting, and smokers who quit smoking have a reduced WBC count [24,25]. One investigation into the residual effects of smoking on WBC count found that smokers who quit a long time ago had WBC counts more like those who had never used tobacco than those who recently stopped smoking [24] but another study found that long-term ex-smokers still had higher WBC counts than non-smokers [25].…”

“…As for the association of past smoking with WBC count, WBC count is related to the amount of time passed since quitting, and smokers who quit smoking have a reduced WBC count [24,25]. One investigation into the residual effects of smoking on WBC count found that smokers who quit a long time ago had WBC counts more like those who had never used tobacco than those who recently stopped smoking [24] but another study found that long-term ex-smokers still had higher WBC counts than non-smokers [25]. Because we could not examine years since quitting smoking among past smokers during follow-up, the relationship between the effects of the decline in WBC count with time [12,13] and indicate that the WBC count is a predictor of IFG or Type II diabetes mellitus because of its association with low-grade inflammation.…”

Quitting Smoking May Restore Hematological Characteristics within Five Years

“…Unlike total leukocyte count, the associations between leukocyte subpopulations and smoking habits, including the effect of quitting, have not been explored extensively. The studies, mostly conducted in men, which did, reported positive associations between smoking and counts of the leukocyte subpopulations, neutrophils, eosinophils, monocytes, and lymphocytes (2,9,10,16).…”

“…The strongest known correlate of the leukocyte count is cigarette smoking, with smokers having higher mean counts than never smokers (1)(2)(3)(4)(5)(6)(10)(11)(12)(13)(14)(15). Some studies reported an increase in leukocyte count with number of cigarettes smoked daily and a decrease after cessation of smoking (9-11, 13, 14).…”