Cervical Esophageal Characteristics in Smokers Versus Non-Smokers: An Ultrasonographic Comparative Analysis

Background/Objective: Smoking is known to be associated with reflux-related mucosal damage and deleterious esophageal outcomes, yet no non-invasive imaging biomarkers of smoking-induced esophageal remodeling have been identified. We aimed to compare cervical esophageal ultrasound morphology between habitual smokers and non-smokers, in terms of esophageal wall thickness, number of sonographically discernable wall layers, and esophageal diameter, and investigate whether smoking is an independent predictor of these findings. Methods: In this cross-sectional study, 60 participants (30 smokers, 30 non-smokers) underwent high-resolution B-mode ultrasound of the cervical esophagus. Examinations were performed in transverse and longitudinal planes. Outcomes included esophageal wall thickness (mm), number of discernible wall layers, and esophageal diameters in transverse and longitudinal planes. Group comparisons used independent t-tests and chi-square tests. Multiple linear regression assessed independent associations with smoking status (adjusting for age and weight). Within smokers, Pearson correlation evaluated relationships between smoking duration and ultrasound outcomes; exploratory subgroup analyses compared smoking modalities. Results: Smokers were older and had higher weight and BMI than non-smokers. Compared with non-smokers, smokers had greater wall thickness (3.06 vs 2.61 mm), more discernible wall layers (5.03 vs 3.60), and larger transverse (11.68 vs 7.87 mm) and longitudinal (12.90 vs 8.26 mm) diameters (all p < 0.001). In regression analysis, smoking status independently predicted wall thickness (B = 0.411 mm, 95% CI 0.243-0.578; p < 0.001). Smoking duration showed significant correlations with the number of visible layers (r = 0.82; p < 0.001) and wall thickness (r = 0.42; p = 0.021). Conclusions: High-frequency ultrasound detected significant differences in cervical esophageal morphology between smokers and non-smokers. Smoking was independently associated with differences in the diameter, thickness, and number of visible layers of the cervical esophagus. Further studies with larger sample sizes, improved exposure assessment, and use of reference standards are needed.