title: The respiratory pyramid: From symptoms to disease in World Trade Center exposed firefighters.
abstract: BACKGROUND
  This study utilizes a four-level pyramid framework to understand the relationship between symptom reports and/or abnormal pulmonary function and diagnoses of airway diseases (AD), including asthma, recurrent bronchitis and COPD/emphysema in WTC-exposed firefighters. We compare the distribution of pyramid levels at two time-points: by 9/11/2005 and by 9/11/2010.
  
  
  METHODS
  We studied 6,931 WTC-exposed FDNY firefighters who completed a monitoring exam during the early period and at least two additional follow-up exams 9/11/2005-9/11/2010.
  
  
  RESULTS
  By 9/11/2005 the pyramid structure was as follows: 4,039 (58.3%) in Level 1, no respiratory evaluation or treatment; 1,608 (23.2%) in Level 2, evaluation or treatment without AD diagnosis; 1,005 (14.5%) in Level 3, a single AD diagnosis (asthma, emphysema/COPD, or recurrent bronchitis); 279 (4.0%) in Level 4, asthma and another AD. By 9/11/2010, the pyramid distribution changed considerably, with Level 1 decreasing to 2,612 (37.7% of the cohort), and Levels 3 (N = 1,530) and 4 (N = 796) increasing to 22.1% and 11.5% of the cohort, respectively. Symptoms, spirometry measurements and healthcare utilization were associated with higher pyramid levels.
  
  
  CONCLUSIONS
  Respiratory diagnoses, even four years after a major inhalation event, are not the only drivers of future healthcare utilization. Symptoms and abnormal FEV-1 values must also be considered if clinicians and healthcare administrators are to accurately anticipate future treatment needs, years after initial exposure.
authors.affiliation: Fire Department of the City of New York, Bureau of Health Services, Brooklyn, New York, USA.
authors.forename: Justin K
authors.initials: JK
authors.lastname: Niles
authors.forename: Mayris P
authors.initials: MP
authors.lastname: Webber
authors.forename: Hillel W
authors.initials: HW
authors.lastname: Cohen
authors.forename: Charles B
authors.initials: CB
authors.lastname: Hall
authors.forename: Rachel
authors.initials: R
authors.lastname: Zeig-Owens
authors.forename: Fen
authors.initials: F
authors.lastname: Ye
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Glaser
authors.forename: Jessica
authors.initials: J
authors.lastname: Weakley
authors.forename: Michael D
authors.initials: MD
authors.lastname: Weiden
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Aldrich
authors.forename: Anna
authors.initials: A
authors.lastname: Nolan
authors.forename: Lara
authors.initials: L
authors.lastname: Glass
authors.forename: Kerry J
authors.initials: KJ
authors.lastname: Kelly
authors.forename: David J
authors.initials: DJ
authors.lastname: Prezant
mesh_terms: D000328:Adult; D017281:Cost of Illness; D061388:Firefighters; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D006296:Health Services / Q000191:economics / Q000706:statistics & numerical data; D006801:Humans; D016015:Logistic Models; D008173:Lung Diseases, Obstructive / Q000175:diagnosis* / Q000191:economics / Q000209:etiology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009519:New York City; D009784:Occupational Diseases / Q000175:diagnosis* / Q000191:economics / Q000209:etiology / Q000628:therapy; D016273:Occupational Exposure / Q000009:adverse effects*; D011379:Prognosis; D047851:September 11 Terrorist Attacks; D012720:Severity of Illness Index; D013147:Spirometry
keywords: World Trade Center; asthma; pulmonary function; treatment outcomes