Objective: Several studies have provided prevalence estimates of posttraumatic stress disorder (PTSD) related to the September 11, 2001 (9/11) attacks in broadly affected populations, although without sufficiently addressing qualifying exposures required for assessing PTSD and estimating its prevalence. A premise that people throughout the New York City area were exposed to the attacks on the World Trade Center (WTC) towers and are thus at risk for developing PTSD has important implications for both prevalence estimates and service provision. This premise has not, however, been tested with respect to DSM-IV-TR criteria for PTSD. This study examined associations between geographic distance from the 9/11 attacks on the WTC and reported 9/11 trauma exposures, and the role of specific trauma exposures in the development of PTSD.

Methods: Approximately 3 years after the attacks, 379 surviving employees (102 with direct exposures, including 65 in the towers, and 277 with varied exposures) recruited from 8 affected organizations were interviewed using the Diagnostic Interview Schedule/Disaster Supplement and reassessed at 6 years. The estimated closest geographic distance from the WTC towers during the attacks and specific disaster exposures were compared with the development of 9/11–related PTSD as defined by the Diagnostic and Statistical Manual, Fourth Edition, Text Revision.

Results: The direct exposure zone was largely concentrated within a radius of 0.1 mi and completely contained within 0.75 mi of the towers. PTSD symptom criteria at any time after the disaster were met by 35% of people directly exposed to danger, 20% of those exposed only through witnessed experiences, and 35% of those exposed only through a close associate’s direct exposure. Outside these exposure groups, few possible sources of exposure were evident among the few who were symptomatic, most of whom had preexisting psychiatric illness.

Conclusions: Exposures deserve careful consideration among widely affected populations after large terrorist attacks when conducting clinical assessments, estimating the magnitude of population PTSD burdens, and projecting needs for specific mental health interventions.

(Disaster Med Public Health Preparedness. 2011;5:S205-S213)

Tens of thousands of workers participated in rescue, recovery, and cleanup activities at the World Trade Center (WTC) site in lower Manhattan after the terrorist attacks on September 11, 2001 (9/11). The collapse of the WTC resulted in the release of a variety of airborne toxicants. To date, respiratory symptoms and diseases have been among the most examined health outcomes in studies of WTC disaster workers. A systematic review of the literature on respiratory health outcomes was undertaken to describe the available information on new onset of respiratory symptoms and diseases among WTC disaster workers after September 11, 2001. Independent risk factors for respiratory health outcomes included being caught in the dust and debris cloud, early arrival at the WTC site, longer duration of work, and delaying mask and respirator use. Methodological challenges in epidemiologic studies of WTC disaster workers involved study design, exposure misclassification, and limited information on potential confounders and effect modifiers. In the 10 years after 9/11, epidemiologic studies of WTC disaster workers have been essential in investigating the respiratory health consequences of WTC exposure. Longitudinal studies along with continued medical surveillance will be vital in understanding the long-term respiratory burden associated with occupational WTC exposure. (Disaster Med Public Health Preparedness. 2011;5:S189–S196)

Objective: We present the longest follow-up, to date, of probable posttraumatic stress disorder (PTSD) after the 2001 terrorist attacks on the World Trade Center (WTC) in New York City firefighters who participated in the rescue/recovery effort.

Methods: We examined data from 11 006 WTC-exposed firefighters who completed 40 672 questionnaires and reported estimates of probable PTSD by year from serial cross-sectional analyses. In longitudinal analyses, we used separate Cox models with data beginning from October 2, 2001, to identify variables associated with recovery from or delayed onset of probable PTSD.

Results: The prevalence of probable PTSD was 7.4% by September 11, 2010, and continued to be associated with early arrival at the WTC towers during every year of analysis. An increasing number of aerodigestive symptoms (hazard ratio [HR] 0.89 per symptom, 95% confidence interval [CI] 0.86-.93) and reporting a decrease in exercise, whether the result of health (HR 0.56 vs no change in exercise, 95% CI 0.41-.78) or other reasons (HR 0.76 vs no change in exercise, 95% CI 0.63-.92), were associated with a lower likelihood of recovery from probable PTSD. Arriving early at the WTC (HR 1.38 vs later WTC arrival, 95% CI 1.12-1.70), an increasing number of aerodigestive symptoms (HR 1.45 per symptom, 95% CI 1.40–1.51), and reporting an increase in alcohol intake since September 11, 2001 (HR 3.43 vs no increase in alcohol intake, 95% CI 2.67-4.43) were associated with delayed onset of probable PTSD.

Conclusions: Probable PTSD continues to be associated with early WTC arrival even 9 years after the terrorist attacks. Concurrent conditions and behaviors, such as respiratory symptoms, exercise, and alcohol use also play important roles in contributing to PTSD symptoms.

(Disaster Med Public Health Preparedness. 2011;5:S197-S203)