Cigarette smoking is associated with an increase in blood monocytes in people with tuberculosis: A cross-sectional study. Issue 37 (16th September 2022)

• Record Type: Journal Article
• Authors: Baluku, Joseph Baruch; Nabwana, Martin; Kansiime, Grace; Nuwagira, Edwin
• Is Part Of: Medicine. Volume 101:Issue 37(2022)
• Page Start: e30737
• Publication Date: 2022-09-16
• Subjects: cigarette -- monocytes -- neutrophils -- smoking -- TB -- tuberculosis; Medicine -- Periodicals; Medicine -- Periodicals; Médecine -- Périodiques; Geneeskunde; Medicine; Periodicals; Periodicals; 610.5
• DOI: 10.1097/MD.0000000000030737
• Languages: English
• ISSNs: 0025-7974

Abstract

Abstract : The effect of smoking on immune responses in people with tuberculosis (TB) is not well elucidated. We aimed to compare peripheral blood counts of CD4+ and CD87 + T-lymphocytes, monocytes, and neutrophils and the CD4:CD8 ratio in TB patients with and without history of cigarette smoking. We further determined factors associated with current smoking. Participants with TB were consecutively enrolled in a cross-sectional study at a national TB treatment center in Uganda in 2018. We compared cell counts and the CD4:CD8 ratio using the median test among never smokers, past smokers (>6 months ago) and current smokers (≤6 months). Factors associated with current smoking were determined using logistic regression. A post hoc analysis for factors associated with an increase in the monocytes was also performed. Of 363 participants, there were 258 (71.1%) never smokers, 50 (13.8%) past smokers, and 55 (15.2%) current smokers. Most current smokers (49.1%) had a high sputum mycobacterial load. They also had the lowest body mass index and the highest axillary temperature. The median (interquartile range [IQR]) monocyte count among current smokers was 815 (540–1425) cells/mm 3 and was significantly higher than that among past smokers (610 (350–900) cells/mm 3, P = .017) and never smokers (560 [400–800] cells/mm 3, P = .001). The monocyte counts positively correlated with the number of cigarettes smoked per day among current smokers ( R = 0.43, P = .006). Current smokers also had higher neutrophil and CD4+ T-cell counts than never smokers. In a multivariable logistic regression model, an increase in the monocyte count was associated with current cigarette smoking (adjusted odds ratio [aOR] = 4.82, 95% confidence interval 1.61–14.39, P = .005). Similarly, current cigarette smoking was independently associated with an increase in the monocyte count (aOR = 1.80, 95% CI 1.39–2.32, P < .001). Cigarette smoking is associated with an increase in the blood monocytes in people with TB in a dose- and time-dependent manner. Further, current smoking is associated with an increase in neutrophils and CD4+ T-lymphocytes. The findings suggest that current smokers have systemic inflammation that is not necessarily beneficial to TB control in TB patients.