Abstract:
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We assessed change over time in the effect of exposure to the World Trade Center rescue/recovery effort on the incidence of physician-diagnosed obstructive airway disease (OAD), chronic rhinosinusitis (CRS) and gastro-esophageal reflux disease (GERD) in 8,968 male firefighters. Exposure was categorized by time of initial exposure. Piecewise exponential survival models were used to estimate incidences by arrival group, with change points in the relative incidences estimated by profile likelihood. For OAD, change points were observed at 15 and 84 months post-9/11, with relative rate (RR) for the high vs. low exposure group of 3.85 [2.41-6.15] prior to 15 months, 1.94 [1.49-2.51] from months 16 to 84, and 1.20 [0.91-1.58] thereafter; no change point was observed for CRS (RR 1.90 [1.56-2.30]) or GERD (RR 1.48 [1.27-1.73]). OAD diagnosis was strongly associated with CRS (RR 4.15 [3.70-4.66]) and GERD (RR 3.18 [2.90-3.48]) diagnoses and partially mediated the association between WTC exposure and both CRS and GERD. Ongoing symptoms post-OAD diagnoses were associated with CRS and GERD diagnoses. This effect of OAD may be biological or may reflect health care utilization practices.
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