Pulmonary function after exposure to the World Trade Center collapse in the New York City Fire Department

Abstract

Rationale: On September 11, 2001, the World Trade Center collapse created an enormous urban disaster site with high levels of airborne pollutants. First responders, rescue and recovery workers, and residents have since reported respiratory symptoms and developed pulmonary function abnormalities.

Objectives: To quantify respiratory health effects of World Trade Center exposure in the New York City Fire Department.

Measurements: Longitudinal study of pulmonary function in 12,079 New York City Fire Department rescue workers employed on or before 09/11/2001. Between 01/01/1997 and 09/11/2002, 31,994 spirometries were obtained and the FEV(1) and FVC were analyzed for differences according to estimated World Trade Center exposure intensity. Adjusted average FEV(1) during the first year after 09/11/2001 was compared with the 5 yr before 09/11/2001. Median time between 09/11/2001 and a worker's first spirometry afterwards was 3 mo; 90% were assessed within 5 mo.

Main results: World Trade Center-exposed workers experienced a substantial reduction in adjusted average FEV(1) during the year after 09/11/2001 (372 ml; 95% confidence interval, 364-381 ml; p < 0.001) This exposure-related FEV(1) decrement equaled 12 yr of aging-related FEV(1) decline. Moreover, exposure intensity assessed by initial arrival time at the World Trade Center site correlated linearly with FEV(1) reduction in an exposure intensity-response gradient (p = 0.048). Respiratory symptoms also predicted a further FEV(1) decrease (p < 0.001). Similar findings were observed for adjusted average FVC.

Conclusions: World Trade Center exposure produced a substantial reduction in pulmonary function in New York City Fire Department rescue workers during the first year after 09/11/2001.

Figure 1.

Study cohort derivation. FDNY = Fire Department of New York City; PFT = pulmonary function test; WTC = World Trade Center.

Figure 2.

FEV₁ distribution in FDNY cohort before and after 09/11/2001. There was a leftward shift in the distribution of percent-predicted FEV₁ (grouped by decile) for the FDNY cohort.

Figure 3.

(A) WTC-related average adjusted FEV₁ losses during the year after 09/11/2001 by arrival time exposure category. WTC-related adjusted average FEV₁ losses with standard errors are depicted. We observed substantial FEV₁ reductions after 09/11/2001, with a significant exposure intensity–response gradient between FDNY rescue workers with increasing arrival time–based WTC exposure intensities. Early-arrival, high-intensity exposure workers experienced an average reduction of 388 ml (95% confidence interval [CI], 370–406 ml). Intermediate-intensity exposure workers experienced an average reduction of 372 ml (95% CI, 363–381 ml). Workers with late-arrival, low-intensity exposure experienced an average decrement of 357 ml (95% CI, 339–374 ml). This linear trend in exposure intensity–response was statistically significant (p = 0.048). Average FEV₁ losses are adjusted for sex, race, height, age, and smoking status. (B) WTC-related average adjusted FEV₁ losses during the year after 09/11/2001 by work assignment exposure category. WTC-related adjusted average FEV₁ losses with standard errors are depicted. We observed substantial FEV₁ reductions after 09/11/2001, with significant differences according to work assignment. Firefighters had an average adjusted decrement of 383 ml (95% CI, 374–393 ml), significantly larger compared with emergency medical service (EMS) workers, who experienced an average reduction of 319 ml (95% CI, 299–340 ml). We did not find significant differences between firefighters who were and who were not assigned to Special Operations Command units. Average FEV₁ losses are adjusted for sex, race, height, age, and smoking status.

Figure 4.

(A) Respiratory symptoms during the year after 09/11/2001 by arrival time exposure category. Rescue workers with early or intermediate exposure had significantly more respiratory symptoms compared with workers with late exposure (p < 0.001). (B) Respiratory symptoms during the year after 09/11/2001 by work assignment exposure category. Firefighters had significantly more respiratory symptoms compared with EMS workers (p < 0.001).