title: Age and Small Airway Imaging Abnormalities in Subjects with and without Airflow Obstruction in SPIROMICS.
abstract: BACKGROUND
  Aging is associated with reduced FEV1to FVC ratio (FEV1/FVC), hyperinflation, and alveolar enlargement, but little is known about how age affects small airways.
  
  
  OBJECTIVE
  To determine if chest computed tomography (CT)-assessed functional small airway would increase with age, even among asymptomatic individuals.
  
  
  METHODS
  We used parametric response mapping analysis of paired inspiratory/expiratory CTs to identify functional small airway abnormality (PRMFSA) and emphysema (PRMEMPH) in the SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study) cohort. Using adjusted linear regression models, we analyzed associations between PRMFSAand age in subjects with or without airflow obstruction. We subdivided participants with normal spirometry based on respiratory-related impairment (6-minute-walk distance <350 m, modified Medical Research Council ≥2, chronic bronchitis, St. George's Respiratory Questionnaire >25, respiratory events requiring treatment [antibiotics and/or steroids or hospitalization] in the year before enrollment).
  
  
  RESULTS
  Among 580 never- and ever-smokers without obstruction or respiratory impairment, PRMFSAincreased 2.7% per decade, ranging from 3.6% (ages 40-50 yr) to 12.7% (ages 70-80 yr). PRMEMPHincreased nonsignificantly (0.1% [ages 40-50 yr] to 0.4% [ages 70-80 yr]; P = 0.34). Associations were similar among nonobstructed individuals with respiratory-related impairment. Increasing PRMFSAin subjects without airflow obstruction was associated with increased FVC (P = 0.004) but unchanged FEV1(P = 0.94), yielding lower FEV1/FVC ratios (P < 0.001). Although emphysema was also significantly associated with lower FEV1/FVC (P = 0.04), its contribution relative to PRMFSAin those without airflow obstruction was limited by its low burden.
  
  
  CONCLUSIONS
  In never- and ever-smokers without airflow obstruction, aging is associated with increased FVC and CT-defined functional small airway abnormality regardless of respiratory symptoms.
authors: 1 Division of Pulmonary and Critical Care Medicine.
authors: Carlos H
authors: CH
authors: Martinez
authors: 2 Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
authors: Alejandro A
authors: AA
authors: Diaz
authors: 1 Division of Pulmonary and Critical Care Medicine.
authors: Catherine
authors: C
authors: Meldrum
authors: 1 Division of Pulmonary and Critical Care Medicine.|3 Pulmonary and Critical Care Medicine Section, Medical Service, and.
authors: Jeffrey L
authors: JL
authors: Curtis
authors: 4 Division of Pulmonary and Critical Care Medicine, University of California Los Angeles Medical Center, Los Angeles, California.
authors: Christopher B
authors: CB
authors: Cooper
authors: 5 Division of Pulmonary and Critical Care Medicine, University of Utah, Salt Lake City, Utah.
authors: Cheryl
authors: C
authors: Pirozzi
authors: 5 Division of Pulmonary and Critical Care Medicine, University of Utah, Salt Lake City, Utah.
authors: Richard E
authors: RE
authors: Kanner
authors: 5 Division of Pulmonary and Critical Care Medicine, University of Utah, Salt Lake City, Utah.|6 Division of Pulmonary and Critical Care Medicine, Veterans Affairs Medical Center, Salt Lake City, Utah.
authors: Robert
authors: R
authors: Paine
authors: 7 Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, California.
authors: Prescott G
authors: PG
authors: Woodruff
authors: 8 Division of Pulmonary and Critical Care Medicine, Wake Forest University, Winston-Salem, North Carolina.
authors: Eugene R
authors: ER
authors: Bleecker
authors: 9 Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland.
authors: Nadia N
authors: NN
authors: Hansel
authors: 10 Division of Pulmonary, Allergy and Critical Care Medicine, Columbia University, New York, New York.
authors: R Graham
authors: RG
authors: Barr
authors: 11 Department of Thoracic Medicine and Surgery, Temple University School of Medicine, Philadelphia, Pennsylvania.
authors: Nathaniel
authors: N
authors: Marchetti
authors: 11 Department of Thoracic Medicine and Surgery, Temple University School of Medicine, Philadelphia, Pennsylvania.
authors: Gerard J
authors: GJ
authors: Criner
authors: 12 Department of Radiology, and.
authors: Ella A
authors: EA
authors: Kazerooni
authors: 13 Department of Radiology and Biomedical Engineering, University of Iowa, Iowa City, Iowa; and.
authors: Eric A
authors: EA
authors: Hoffman
authors: 12 Department of Radiology, and.|14 Center for Molecular Imaging, University of Michigan, Ann Arbor, Michigan.
authors: Brian D
authors: BD
authors: Ross
authors: 12 Department of Radiology, and.|14 Center for Molecular Imaging, University of Michigan, Ann Arbor, Michigan.
authors: Craig J
authors: CJ
authors: Galban
authors: 16 Geriatric Research and Education Clinical Center, VA Ann Arbor Healthcare System, Ann Arbor, Michigan.|15 Department of Family Medicine, University of Michigan Health System, Ann Arbor, Michigan.
authors: Christine T
authors: CT
authors: Cigolle
authors: 1 Division of Pulmonary and Critical Care Medicine.
authors: Fernando J
authors: FJ
authors: Martinez
authors: 1 Division of Pulmonary and Critical Care Medicine.
authors: MeiLan K
authors: MK
authors: Han
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology* / Q000502:physiology; D000402:Airway Obstruction / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D015999:Multivariate Analysis; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D012907:Smoking / Q000009:adverse effects / Q000473:pathology*; D013147:Spirometry; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity / Q000502:physiology
keywords: aging; geriatrics; imaging analysis; lung function; spirometry