title: Imaging Phenotype of Occupational Endotoxin-Related Lung Function Decline.
abstract: Although occupational exposures contribute to a significant proportion of obstructive lung disease, the phenotype of obstructive lung disease associated with work-related organic dust exposure independent of smoking remains poorly defined.
  
  
  
  We identified the relative contributions of smoking and occupational endotoxin exposure to parenchymal and airway remodeling as defined by quantitative computed tomography (CT).
  
  
  
  The Shanghai Textile Worker Study is a longitudinal study of endotoxin-exposed cotton workers and endotoxin-unexposed silk workers that was initiated in 1981. Spirometry, occupational endotoxin exposure, and smoking habits were assessed at 5-year intervals. High-resolution computed tomography (CT) was performed in 464 retired workers in 2011, along with quantitative lung densitometric and airway analysis.
  
  
  
  Significant differences in all CT measures were noted across exposure groups. Occupational endotoxin exposure was associated with a decrease (-1.3%) in percent emphysema (LAAI-950), a 3.3-Hounsfield unit increase in 15th percentile density, an 18.1-g increase in lung mass, and a 2.3% increase in wall area percent. Current but not former smoking was associated with a similar CT phenotype. Changes in LAAI-950 were highly correlated with 15th percentile density (correlation -1.0). Lung mass was the only measure associated with forced expiratory volume in 1 sec (FEV1) decline, with each 10-g increase in lung mass associated with an additional loss (-6.1 mL) of FEV1 (p = 0.001) between 1981 and 2011.
  
  
  
  There are many similarities between the effects of occupational endotoxin exposure and those of tobacco smoke exposure on lung parenchyma and airway remodeling. The effects of occupational endotoxin exposure appear to persist even after the cessation of exposure. LAAI-950 may not be a reliable indicator of emphysema in subjects without spirometric impairment. Lung mass is a CT-based biomarker of accelerated lung function decline.
  
  
  
  Lai PS, Hang J, Zhang F, Sun J, Zheng BY, Su L, Washko GR, Christiani DC. 2016. Imaging phenotype of occupational endotoxin-related lung function decline. Environ Health Perspect 124:1436-1442; http://dx.doi.org/10.1289/EHP195.
authors.affiliation: Division of Pulmonary and Critical Care, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: Peggy S
authors.initials: PS
authors.lastname: Lai
authors.forename: Jing-Qing
authors.initials: JQ
authors.lastname: Hang
authors.forename: Feng-Ying
authors.initials: FY
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: Bu-Yong
authors.initials: BY
authors.lastname: Zheng
authors.forename: Li
authors.initials: L
authors.lastname: Su
authors.forename: George R
authors.initials: GR
authors.lastname: Washko
authors.forename: David C
authors.initials: DC
authors.lastname: Christiani
mesh_terms: D000368:Aged; D000395:Air Pollutants, Occupational / Q000633:toxicity; D056151:Airway Remodeling; D002681:China; D004731:Endotoxins / Q000633:toxicity*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008168:Lung / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000503:physiopathology; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000000981:diagnostic imaging*; D016273:Occupational Exposure; D000072356:Parenchymal Tissue / Q000000981:diagnostic imaging / Q000502:physiology*; D012129:Respiratory Function Tests; D012907:Smoking / Q000503:physiopathology; D014057:Tomography, X-Ray Computed
chemical_list: D000395:Air Pollutants, Occupational; D004731:Endotoxins