title: Cigarette smoking and airway wall thickness on CT scan in a multi-ethnic cohort: the MESA Lung Study.
abstract: BACKGROUND
  Autopsy studies show that smoking contributes to airway wall hyperplasia and narrowing of the airway lumen. Studies of smoking and airway measures on computed tomography (CT) scan are limited to case-control studies of measures that combine airway lumen and wall thickness.
  
  
  OBJECTIVE
  We hypothesized that cumulative cigarette smoking would be associated with increased airway wall thickness in a large, population-based cohort.
  
  
  METHODS
  The Multi-Ethnic Study of Atherosclerosis enrolled participants age 45-84 years from the general population. Smoking history was assessed via standardized questionnaire items; current smoking was confirmed in half the cohort with cotinine. Airway lumen and wall thickness were measured in two dimensions in posterior basal segmental bronchi on cardiac-gated CT scans. Analyses were adjusted for age, gender, genetic ancestry, education, height, weight, asthma history, particulate matter, scanner type, and scanner current.
  
  
  RESULTS
  Half of the 7898 participants had smoked and 14% were current smokers. Pack-years of smoking were associated with thicker airway walls (mean increase 0.002 mm per ten pack-years [95% CI: 0.00002, 0.004] p = 0.03). Current smoking was associated with narrower airway lumens (mean decrease -0.11 mm [95% CI: -0.2, -0.02] p = 0.02). There was no evidence that either association was modified by genetic ancestry, and findings persisted among participants without clinical disease.
  
  
  CONCLUSIONS
  Long-term cigarette smoking was associated with subclinical increases in wall thickness of sub-segmental airways whereas current smoking was associated with narrower airway lumen diameters. Smoking may contribute to airway wall thickening prior to the development of overt chronic obstructive pulmonary disease.
authors.affiliation: Columbia University, New York, NY 10032, USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Donohue
authors.forename: Eric A
authors.initials: EA
authors.lastname: Hoffman
authors.forename: Heather
authors.initials: H
authors.lastname: Baumhauer
authors.forename: Junfeng
authors.initials: J
authors.lastname: Guo
authors.forename: Matthew
authors.initials: M
authors.lastname: Budoff
authors.forename: John H M
authors.initials: JH
authors.lastname: Austin
authors.forename: Ravi
authors.initials: R
authors.lastname: Kalhan
authors.forename: Steven
authors.initials: S
authors.lastname: Kawut
authors.forename: Russell
authors.initials: R
authors.lastname: Tracy
authors.forename: R Graham
authors.initials: RG
authors.lastname: Barr
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001980:Bronchi / Q000473:pathology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000208:ethnology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000208:ethnology / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D014481:United States / Q000453:epidemiology