Cigarette Smoking, and Blood Monocyte Count Correlate with Chronic Lung Injuries and Mortality

Rahul G Sangani; Vishal Deepak; Javeria Anwar; Zalak Patel; Andrew J Ghio

doi:10.2147/COPD.S397667

Cigarette Smoking, and Blood Monocyte Count Correlate with Chronic Lung Injuries and Mortality

Int J Chron Obstruct Pulmon Dis. 2023 Apr 1:18:431-446. doi: 10.2147/COPD.S397667. eCollection 2023.

Authors

Rahul G Sangani¹, Vishal Deepak¹, Javeria Anwar¹, Zalak Patel², Andrew J Ghio³

Affiliations

¹ Section of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, West Virginia University, Morgantown, WV, USA.
² Department of Radiology, West Virginia University, Morgantown, WV, USA.
³ US EPA, Chapel Hill, NC, USA.

Abstract

Background: Cigarette smoking (CS)-related monocytosis contributes to the development of chronic lung injuries via complex mechanisms. We aim to determine correlations between measures of CS and monocytes, their capacities to predict chronic lung diseases, and their associations with mortality.

Methods: A single-center retrospective study of patients undergoing surgical resection for suspected lung nodules/masses was performed. CS was quantified as cigarettes smoked per day (CPD), duration of smoking, composite pack years (CPY), current smoking status, and smoking cessation years. A multivariate logistic regression analysis was performed.

Results: Of 382 eligible patients, 88% were ever smokers. In this group, 45% were current smokers with mean CPD of 27.2±40.0. CPY and duration of smoking showed positive linear correlations with percentage monocyte count. Physiologically, CPY was associated with progressive obstruction, hyperinflation, and reduced diffusion capacity (DL_CO). Across the quartiles of smoking, there was an accumulation of radiologic and histologic abnormalities. Anthracosis and emphysema were associated with CPD, while lung cancer, respiratory bronchiolitis (RB), emphysema, and honeycombing were statistically related to duration of smoking. Analysis using consecutive CPY showed associations with lung cancer (≥10 and <30), fibrosis (≥20 and <40), RB (≥50), anthracosis and emphysema (≥10 and onwards). Percentage monocytes correlated with organizing pneumonia (OP), fibrosis, and emphysema. The greater CPY increased mortality across the groups. Significant predictors of mortality included percentage monocyte, anemia, GERD, and reduced DL_CO.

Conclusion: Indices of CS and greater monocyte numbers were associated with endpoints of chronic lung disease suggesting a participation in pathogenesis. Application of these easily available metrics may support a chronology of CS-induced chronic lung injuries. While a relative lesser amount of smoking can be associated with lung cancer and fibrosis, greater CPY increases the risk for emphysema. Monocytosis predicted lung fibrosis and mortality. Duration of smoking may serve as a better marker of monocytosis and associated chronic lung diseases.

Keywords: emphysema; lung cancer; monocyte; mortality; pulmonary fibrosis; smoking.

MeSH terms

Anthracosis* / complications
Anthracosis* / pathology
Cigarette Smoking*
Emphysema*
Humans
Lung / pathology
Lung Injury* / diagnosis
Lung Injury* / etiology
Lung Neoplasms* / pathology
Monocytes / pathology
Pulmonary Disease, Chronic Obstructive* / etiology
Pulmonary Emphysema* / etiology
Pulmonary Fibrosis*
Retrospective Studies

Grants and funding

There is no funding to report.