Cigarette Smoking Effects on Asthma Pathophysiology

Cigarette smoke triggers a complex cascade of inflammatory and structural changes in the asthmatic airway. Constituents of tobacco smoke breach the epithelial barrier, generating reactive oxygen species and activating innate immune receptors. These insults skew the immune equilibrium towards type 2 (Th2) and type 17 (Th17) responses, characterised by eosinophil and neutrophil recruitment, epithelial goblet cell hyperplasia and airway remodelling. Chronic smoke exposure also impairs corticosteroid efficacy through oxidative inactivation of signalling proteins and reductions in histone deacetylase activity, contributing to persistent low-grade systemic inflammation and heightened bronchial hyperreactivity. Functional consequences include accelerated decline in lung function, more frequent exacerbations and poor symptom control. Smoking cessation remains the cornerstone of intervention, but adjunctive strategies targeting oxidative stress pathways and novel immunomodulators show promise for patients who continue to smoke or have a history of smoking.

Research from Nature Portfolio

Recent clinical analyses have delineated distinct phenotypes among current and former smokers with asthma. A multicentre study of Chinese adults revealed that current smokers exhibit worse asthma control and higher inhaled corticosteroid doses than former smokers, with smoking duration and pack-years correlating with poorer control. In a large Korean community survey, both active and passive smoking were independently associated with increased wheezing frequency and asthma aggravations; early smoking initiation and cumulative pack-years showed dose–response relations with symptom severity. Complementing these observations, a Mendelian randomisation investigation using smoking-related genetic variants provided evidence that tobacco exposure causally increases asthma risk, emphasising the direct role of smoking in disease development rather than confounding lifestyle factors.

Cigarette Smoking Effects on Asthma Pathophysiology publication trend

The graph below shows the total number of articles in cigarette smoking effects on asthma pathophysiology across all publications each year (not limited to Nature Index journals).

Technical terms

Th2 response: A type of immune reaction dominated by T helper-2 cells that promotes eosinophilic inflammation and IgE production.

Th17 response: An immune pathway driven by T helper-17 cells, associated with neutrophilic inflammation and airway remodelling.

Oxidative stress: Cellular damage caused by reactive oxygen species exceeding antioxidant defences.

Nrf2: A transcription factor that regulates antioxidant gene expression in response to oxidative stress.

ICS (Inhaled Corticosteroids): Anti-inflammatory medications commonly used in asthma control that may be less effective in smokers.

Pack-years: A measure of smoking history calculated as the number of cigarette packs smoked per day multiplied by years of smoking.

References

1. Different clinical characteristics of current smokers and former smokers with asthma: a cross-sectional study of adult asthma patients in China. Scientific Reports (2023).
2. Active and passive smoking impacts on asthma with quantitative and temporal relations: A Korean Community Health Survey. Scientific Reports (2018).
3. Investigating the causal effect of smoking on hay fever and asthma: a Mendelian randomization meta-analysis in the CARTA consortium. Scientific Reports (2017).
4. Longitudinal association of exclusive and dual use of cigarettes and cigars with asthma exacerbation among US adults: a cohort study. Respiratory Research (2024).
5. A CpG-Oligodeoxynucleotide Suppresses Th2/Th17 Inflammation by Inhibiting IL-33/ST2 Signaling in Mice from a Model of Adoptive Dendritic Cell Transfer of Smoke-Induced Asthma. International Journal of Molecular Sciences (2023).
6. Cigarette Smoking and Asthma. The Journal of Allergy and Clinical Immunology In Practice (2022).