Rationale: The World Trade Center (WTC) collapse generated caustic airborne particulates that caused chronic rhinosinusitis in exposed Fire Department of New York firefighters. Surgery was performed when symptoms remained uncontrolled despite medical management.
Objectives: To identify predictors of surgical intervention for chronic rhinosinusitis in firefighters exposed to airborne irritants at the WTC collapse site.
Methods: We assessed in 8,227 firefighters with WTC exposure between September 11, 2001 (9/11), and September 25, 2001, including WTC-site arrival time, months of rescue and recovery work, and eosinophil concentration measured between 9/11 and March 10, 2003. We assessed the association of serum cytokines and immunoglobulins with eosinophil concentration and surgery for rhinosinusitis in 112 surgical cases and 376 control subjects with serum available from the first 6 months after exposure to the WTC collapse site.
Measurements and main results: Between 9/11 and March 10, 2015, the surgery rate was 0.47 cases per 100 person-years. In the first 18 months post-9/11, surgical patients had higher mean blood eosinophil levels than study cohort patients (219 ± 155 vs. 191 ± 134; P < 0.0001). Increased surgery risk was associated with increasing blood eosinophil counts (hazard ratio [HR], 1.12 per 100 cells/μl; 95% confidence interval [CI], 1.07-1.17; P < 0.001); arriving at the WTC site on 9/11 or September 12, 2001 (HR, 1.43; 95% CI, 1.04-1.99; P = 0.03); and working 6 months or longer at the WTC site (HR, 1.48; 95% CI, 1.14-1.93; P < 0.01). Median blood eosinophil levels for surgical patients were above levels for the cohort in all 18-month intervals March 11, 2000, through March 10, 2015, using 51,163 measurements representing 97,733 person-years of observation. Increasing age, increasing IL-17A, and low IgA in serum from 2001 to 2002 predicted blood eosinophil concentration in surgical patients but not in control subjects (R(2) = 0.26, P < 0.0001; vs. R(2) = 0.008, P = 0.56).
Conclusions: Increasing blood eosinophil concentration predicts surgical intervention for chronic rhinosinusitis, particularly in those with intense acute and prolonged exposure to airborne irritants. WTC-exposed Fire Department of New York firefighters who underwent irritant-associated sinus surgery are immunologically different from the cohort. Surgical patients have a higher blood eosinophil levels that is associated with mediators of mucosal immunity.
Keywords: cohort studies; eosinophils; otolaryngology surgery; particulate matter; sinusitis.