title: CT-quantified emphysema in male heavy smokers: association with lung function decline.
abstract: BACKGROUND
  Emphysema and small airway disease both contribute to chronic obstructive pulmonary disease (COPD), a disease characterised by accelerated decline in lung function. The association between the extent of emphysema in male current and former smokers and lung function decline was investigated.
  
  
  METHODS
  Current and former heavy smokers participating in a lung cancer screening trial were recruited to the study and all underwent CT. Spirometry was performed at baseline and at 3-year follow-up. The 15th percentile (Perc15) was used to assess the severity of emphysema.
  
  
  RESULTS
  2085 men of mean age 59.8 years participated in the study. Mean (SD) baseline Perc15 was -934.9 (19.5) HU. A lower Perc15 value correlated with a lower forced expiratory volume in 1 s (FEV(1)) at baseline (r=0.12, p<0.001). Linear mixed model analysis showed that a lower Perc15 was significantly related to a greater decline in FEV(1) after follow-up (p<0.001). Participants without baseline airway obstruction who developed it after follow-up had significantly lower mean (SD) Perc15 values at baseline than those who did not develop obstruction (-934.2 (17.1) HU vs -930.2 (19.7) HU, p<0.001).
  
  
  CONCLUSIONS
  Greater baseline severity of CT-detected emphysema is related to lower baseline lung function and greater rates of lung function decline, even in those without airway obstruction. CT-detected emphysema aids in identifying non-obstructed male smokers who will develop airflow obstruction.
authors.affiliation: Division of Heart and Lungs, Department of Respiratory Medicine, University Medical Centre Utrecht, Heidelberglaan 100, 3508 GA Utrecht, The Netherlands. f.a.a.mohamedhoesein@umcutrecht.nl
authors.forename: Firdaus A A
authors.initials: FA
authors.lastname: Mohamed Hoesein
authors.forename: Bartjan
authors.initials: B
authors.lastname: de Hoop
authors.forename: Pieter
authors.initials: P
authors.lastname: Zanen
authors.forename: Hester
authors.initials: H
authors.lastname: Gietema
authors.forename: Cas L J J
authors.initials: CL
authors.lastname: Kruitwagen
authors.forename: Bram
authors.initials: B
authors.lastname: van Ginneken
authors.forename: Ivana
authors.initials: I
authors.lastname: Isgum
authors.forename: Christian
authors.initials: C
authors.lastname: Mol
authors.forename: Rob J
authors.initials: RJ
authors.lastname: van Klaveren
authors.forename: Akkelies E
authors.initials: AE
authors.lastname: Dijkstra
authors.forename: Harry J M
authors.initials: HJ
authors.lastname: Groen
authors.forename: H Marike
authors.initials: HM
authors.lastname: Boezen
authors.forename: Dirkje S
authors.initials: DS
authors.lastname: Postma
authors.forename: Mathias
authors.initials: M
authors.lastname: Prokop
authors.forename: Jan-Willem J
authors.initials: JW
authors.lastname: Lammers
mesh_terms: D018450:Disease Progression; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011656:Pulmonary Emphysema / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015203:Reproducibility of Results; D012131:Respiratory Insufficiency / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D012907:Smoking / Q000009:adverse effects*; D013147:Spirometry; D013997:Time Factors; D014057:Tomography, X-Ray Computed