Association of Obesity with Quantitative Chest CT Measured Airway Wall Thickness in WTC Workers with Lower Airway Disease

• Published in: Lung Vol. 197; no. 4; pp. 517 - 522
• Main Authors: de la Hoz, Rafael E., Liu, Xiaoyu, Celedón, Juan C., Doucette, John T., Jeon, Yunho, Reeves, Anthony P., San José Estépar, Raúl
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2019; Springer; Springer Nature B.V
• Subjects: Allergic diseases; Analysis; Body mass; Body Mass Index; Body size; Body weight gain; Bronchi - diagnostic imaging; Bronchi - physiopathology; Bronchial Diseases - diagnostic imaging; Bronchial Diseases - etiology; Bronchial Diseases - physiopathology; Bronchus; Case-Control Studies; Chest; Complications and side effects; Computed tomography; Control methods; Humans; Lungs; Medical research; Medicine; Medicine & Public Health; Medicine, Experimental; Multidetector Computed Tomography; NCT; NCT00608764; Obesity; Obesity - complications; Obesity - diagnostic imaging; Occupational Diseases - diagnostic imaging; Occupational Diseases - etiology; Occupational Diseases - physiopathology; Occupational exposure; Occupational Exposure - adverse effects; Occupational Lung Disease; Pneumology/Respiratory System; Predictive Value of Tests; Regression analysis; Regression models; Respiratory tract diseases; Risk Factors; September 11 Terrorist Attacks; Smoke Inhalation Injury - diagnostic imaging; Smoke Inhalation Injury - etiology; Smoke Inhalation Injury - physiopathology; Wall thickness; Workers; Bronchial disease; Smoke inhalation injury; Computer-assisted image processing; Obesity; World Trade Center Attack, 2001; Multidetector computed tomography
• ISSN: 0341-2040; 1432-1750
• DOI: 10.1007/s00408-019-00246-z

Background We previously reported that wall area percent (WAP), a quantitative CT (QCT) indicator of airway wall thickness and, presumably, inflammation, is associated with adverse longitudinal expiratory flow trajectories in WTC workers, but that obesity and weight gain also seemed to be independently predictive of the latter. Previous studies have reported no association between WAP and obesity, so we investigated that association in nonsmoking WTC-exposed individuals and healthy unexposed controls. Methods We assessed WAP using the Chest Imaging Platform QCT system in a segmental bronchus in 118 former WTC workers, and 89 COPDGene® WTC-unexposed and asymptomatic subjects. We used multiple regression to model WAP vs. body mass index (BMI) in the two groups, adjusting for important subject and CT image characteristics. Results Unadjusted analyses revealed significant differences between the two groups with regards to WAP, age, gender, scan pixel spacing and slice interval, but not BMI or total lung capacity. In adjusted analysis, there was a significant interaction between BMI and WTC exposure on WAP. BMI was significantly and positively associated with WAP in the WTC group, but not in the COPDGene® group, but stratified analyses revealed that the effect was significant in WTC subjects with clinical evidence of lower airway disease (LAD). Discussion Unlike non-diseased subjects, BMI was significantly associated with WAP in WTC workers and, in stratified analyses, the association was significant only among those with LAD. Our findings suggest that this adverse effect of obesity on airway structure and inflammation may be confined to already diseased individuals.