Mid-Term Findings from Selected Works

More than 46,000 Registry enrollees participated in the Registry’s second survey (Wave 2) in 2006-2007. The Wave 2 survey, following the first survey (Wave 1, 2003-2004), helped the Registry determine the extent of physical and mental health conditions among enrollees. New findings, five to six years after 9/11, have been published and some of the major findings are below.

Post-Traumatic Stress Disorder (PTSD)

New and persistent posttraumatic symptoms among adult enrollees

Among Registry enrollees, probable PTSD was one of the two most commonly reported health conditions 5 to 6 years after 9/11. Nearly 20% reported new post-traumatic stress symptoms 5 to 6 years later, an increase from 14% in 2003 and 2004. The highest increase was observed among rescue and recovery workers.  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 low-income (32%) and Hispanic enrollees (31%), and those passing by on 9/11 (23%), including commuters and tourists. (Brackbill et al.; Journal of the American Medical Association, 2009)

Respiratory Health

Comorbid lower respiratory symptoms and PTSD among 9/11 responders

Among the 14,867 responders in the Registry who completed the baseline and Wave 2 surveys, nearly 25% reported persistent lower respiratory symptoms and 17% reported probable PTSD. Nearly 10% had both lower respiratory symptoms and probable PTSD 5 to 6 years after 9/11. The co-occurrence of lower respiratory symptoms and PTSD among responders was associated with more severe respiratory and mental health symptoms, disability and poor quality of life. These findings indicate a need for comprehensive health screenings and coordinated treatment. (Friedman et al.; American Journal of Industrial Medicine, 2013)

Incidence of Asthma

Asthma was the second most commonly reported conditions 5 to 6 years following 9/11. About 10% of enrollees reported they had developed new asthma, with most diagnosed in the first 16 months after 9/11. Intense dust cloud exposure was a major risk factor for incidence of asthma. The rate of newly diagnosed 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. (Brackbill et al.; Journal of the American Medical Association, 2009)



Injury as a result of 9/11, including broken bones or burns, increased the risk of chronic disease 5-6 years after 9/11, according to a study of more than 14,000 enrollees who reported no previous diagnosis of heart disease, respiratory disease, diabetes or cancer. Enrollees who reported more than one injury were twice as likely to also report respiratory illness as those who were not injured. Enrollees with multiple injuries and probable PTSD were three times more likely to report heart disease than those with no injuries and no PTSD. (Brackbill et al.; American Journal of Epidemiology, 2014)

Cardiovascular disease hospitalizations

Researchers linked data for 46,346 Registry enrollees living in New York State to a state hospital-discharge reporting system that records medical diagnoses. They found 1,151 heart disease (including hardening of the arteries and heart attack) and 284 stroke-related hospitalizations occurring in 2003-2010. Male rescue/recovery workers with high levels of WTC exposure were at 82% higher risk for heart disease hospitalization compared to those with low levels of exposure; women who had PTSD when they enrolled in the Registry faced a 32% higher risk compared to women without PTSD. Men with PTSD at enrollment were at a 53% higher risk of hospitalization due to stroke compared with men without PTSD. (Jordan et al; Journal of the American Heart Association, 2013)


The Registry’s first cancer analysis identified new cancer cases through record linkage with 11 state cancer registries, focusing on cancers diagnosed in 2007-2008. Through this time, 1187 new cases of cancer were reported among eligible enrollees and 439 of these cases were rescue/recovery workers. The study found significantly increased prostate and thyroid cancer and multiple myeloma among rescue and recovery workers. There was no increased risk among enrollees not involved in rescue/recovery work. Further follow-up studies will provide more information for cancers with longer latency periods. (Li et al.; Journal of the American Medical Association, 2012)

Mortality Risk

Deaths occurring in 2003-2009 in the Registry were identified through linkage to New York City vital records and the National Death Index. For non-rescue/recovery enrollees, intermediate and high levels of 9/11 related exposures were associated with mortality. Non-rescue/recovery workers who were more highly exposed to the WTC disaster may be at an increased mortality risk, especially cardiac-related, in comparison to those less exposed. In comparison to the general population, the mortality rate among enrollees was lower than expected. This study serves as a baseline for future follow-up. (Jordan et al.; The Lancet, 2011)