Latest Findings

In August 2009, we released findings based on Registry data collected in 2006 and 2007.

Among the 50,000 study participants, probable post-traumatic stress disorder (PTSD) and new asthma were the most commonly reported conditions 5 to 6 years after 9/11. People caught in the dust cloud on 9/11 had the highest risk for developing these conditions. The findings – published in the Journal of the American Medical Association – provide the most comprehensive look at the current health of people directly exposed to the World Trade Center (WTC) disaster:

Post-Traumatic Stress Disorder (PTSD)

• 19% reported new post-traumatic stress symptoms 5 to 6 years later, an increase from 14% in 2003 and 2004.
• More than half (52%) who reported post-traumatic stress symptoms said they did not receive treatment in the previous year.
• The rate of PTSD was highest among those passing by on 9/11 (23%), including commuters and tourists.

Asthma

• 10% reported they had developed new asthma, with most diagnosed in the first 16 months after 9/11. The number reporting new onset of asthma symptoms was not elevated 5 to 6 years after 9/11. The rate of new asthma was highest (12%) among rescue and recovery workers who worked on the debris pile on 9/11.
• The findings also suggest that people who found a heavy layer of dust when they returned to their homes or offices were at a higher risk for developing new asthma.

Source

Brackbill RM, Hadler JL, DiGrande L, et al. Asthma and Posttraumatic Stress Symptoms 5 to 6 Years Following Exposure to the World Trade Center Terrorist Attack. JAMA: The Journal of the American Medical Association. 2009 August 5; 302(5): 502-16.

Past Findings

The following findings are based on Registry data collected in 2003 and 2004.

Estimated Number Exposed

More than 410,000 people were directly exposed to the WTC disaster, including: 

• More than 91,000 rescue and recovery workers and volunteers
• More than 57,000 residents south of Canal Street
• About 15,000 children and staff in schools (pre K-12) south of Canal Street
• More than 360,000 building occupants, residents and people passing by

Note: About 26% fell into more than 1 group, with the greatest overlap among those in lower Manhattan on  September 11 who  were also a rescue and recovery worker or lived in the area or both.

More Information:
Measuring and maximizing coverage
Explanation and Calculation of Outcome Rates
Sample Building and Denominator Estimation

Exposures

Among the 71,437 people enrolled in the WTC Health Registry:

• 70% reported witnessing traumatizing events on 9/11, such as seeing people running away from the dust cloud (53%) or collapsing buildings (47%), seeing people  injured or killed (33%) or  falling or jumping from the towers (29%) or seeing an airplane hit the towers (29%)
• More than half (51%) reported being caught in the dust cloud on 9/11
• 13% suffered an injury
• 61% of adult residents reported  they evacuated their homes on or after 9/11, with 9% returning as early as 2 days later
• 83% of building occupants reported they evacuated their workplaces on 9/11 

Sources

Farfel M, DiGrande L, Brackbill R et al. An Overview of 9/11 Experiences and Respiratory and Mental Health Conditions among World Trade Center Health Registry Enrollees. Journal of Urban Health: Bulletin of the New York Academy of Medicine. 2008 November; 85(6): 880-909.

Murphy J, Brackbill RM, Thalji L et al. Measuring and Maximizing Coverage in the World Trade Center Health Registry. Statistics In Medicine. 2007. 26: 1688-701.