Estimating the time interval between exposure to the world trade center disaster and incident diagnoses of obstructive airway disease

Michelle S. Glaser, Mayris P. Webber, Rachel Zeig-Owens, Jessica Weakley, Xiaoxue Liu, Fen Ye, Hillel W. Cohen, Thomas K. Aldrich, Kerry J. Kelly, Anna Nolan, Michael D. Weiden, David J. Prezant, Charles B. Hall

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Respiratory disorders are associated with occupational and environmental exposures. The latency period between exposure and disease onset remains uncertain. The World Trade Center (WTC) disaster presents a unique opportunity to describe the latency period for obstructive airway disease (OAD) diagnoses. This prospective cohort study of New York City firefighters compared the timing and incidence of physician-diagnosed OAD relative to WTC exposure. Exposure was categorized by WTC arrival time as high (on the morning of September 11, 2001), moderate (after noon on September 11, 2001, or on September 12, 2001), or low (during September 13-24, 2001). We modeled relative rates and 95% confidence intervals of OAD incidence by exposure over the first 5 years after September 11, 2001, estimating the times of change in the relative rate with change point models. We observed a change point at 15 months after September 11, 2001. Before 15 months, the relative rate for the high- versus low-exposure group was 3.96 (95% confidence interval: 2.51, 6.26) and thereafter, it was 1.76 (95% confidence interval: 1.26, 2.46). Incident OAD was associated with WTC exposure for at least 5 years after September 11, 2001. There were higher rates of new-onset OAD among the high-exposure group during the first 15 months and, to a lesser extent, throughout follow-up. This difference in relative rate by exposure occurred despite full and free access to health care for all WTC-exposed firefighters, demonstrating the persistence of WTC-associated OAD risk.

Original languageEnglish (US)
Pages (from-to)272-279
Number of pages8
JournalAmerican Journal of Epidemiology
Issue number3
StatePublished - Aug 1 2014


  • World Trade Center
  • change point model
  • latency
  • obstructive airway disease
  • occupational exposure
  • rescue/recovery workers

ASJC Scopus subject areas

  • Epidemiology


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