August 4, 2009 — People directly exposed to the 2001 World Trade Center disaster were four times more likely than other people to report post-traumatic stress symptoms in 2006-2007, a new study shows. While many studies have documented the adverse physical and mental health conditions associated with 9/11, most have focused on the short-term health effects within the first three years following the disaster. In a new study, "Asthma and Post-traumatic Stress Symptoms 5 to 6 Years Following Exposure to the World Trade Center Terrorist Attack," the Health Department and the Centers for Disease Control and Prevention (CDC) examined the nation's largest cohort of directly exposed people. Approximately 50,000 study participants reported their symptoms in a survey completed online, by mail or over the telephone; their medical records were not reviewed. The study, published in the Journal of the American Medical Association, also found elevated asthma rates among exposed people. But new asthma diagnoses were more likely to be reported in the first 16 months after 9/11 than later, in 2004-2006. The full report, available at http://jama.ama-assn.org/, suggests that post-traumatic stress symptoms and asthma, which often occur together, are the major health ramifications of the World Trade Center attack.Â
The 50,000 study participants included survivors of the Twin Towers' collapse, rescue-and-recovery workers, and volunteers who responded early or worked at the WTC site for a long time. They also included passers-by, people who returned to work in downtown Manhattan, and people who lived nearby.
Among WTC-exposed adults with no previous history of post-traumatic stress, the proportion reporting symptoms increased from 14% in the 2003-2004 survey to 19% in 2006-2007, roughly four times the rate typically seen among U.S. adults. The most traumatized people were the passers-by, such as commuters and tourists. Some 23% reported symptoms in 2006-2007. More than half (52%) of participants who reported post-traumatic stress symptoms at the time of the survey said they had not received treatment in the previous year. The WTC Health Registry, in conjunction with the New York City Health and Hospitals Corporation's WTC Environmental Health Center, has begun outreach efforts to ensure that enrollees with any WTC-related health condition receive active referrals to treatment.
Adults exposed to the disaster experienced a rapid spike in asthma diagnoses immediately after the attacks. New cases were diagnosed at 6 times the national adult rate during the first 4 months after 9/11. By the time of the 2006-2007 survey, 10% of the study participants had been newly diagnosed with asthma. While the number of people reporting new diagnoses was still elevated three to five years later, the number reporting new onset of symptoms was not. Of all participants, rescue and recovery workers had the highest rate (12%) of new asthma, and their risk doubled if they arrived at the WTC site on 9/11 or worked longer than 90 days. The new findings also suggest that people who found a heavy layer of dust when they returned to their homes or offices were at higher risk for developing new asthma.
"This study would not have been possible without the cooperation of the tens of thousands enrollees in our World Trade Center Health Registry who responded to our second survey in 2006 and 2007," said Dr. Thomas Farley, New York City Health Commissioner. "Thanks to their participation, we can better understand the long-term health care needs of people with 9/11-related illness years later, especially those who have not been in care or getting proper treatment."
"The results of this report provide the most comprehensive look at the current health of Americans who were directly exposed to the World Trade Center disaster," said Robert Brackbill, an epidemiologist from the federal Agency for Toxic Substances and Disease Registry who was primary author of the study. "We learned that while symptoms of post-traumatic stress resolved for some between our first and second surveys, symptoms for others actually worsened between the two surveys."
"Thanks to the cooperation of our enrollees all over the United States, this study has the potential to help communities, government agencies and first responders prepare for future disaster responses," said Lorna Thorpe, the Health Department's deputy commissioner for epidemiology and a co-author of the study. "Our findings confirm that, after a terrorist attack, physical and mental health conditions can persist for years in directly-exposed people."
About the data
The study was based on data from the World Trade Center Health Registry. The Health Department and the CDC monitored more than 71,000 people who voluntarily registered and were directly exposed to the WTC disaster. Information on their experiences and health status was first collected between 2003 and 2004 (two to three years after the event) and again from 2006 to 2007 (five to six years post-event). More than 46,000 adults, or 68% of the original enrollees, participated in both of surveys.Â
About the journal
These findings were published in The Journal of the American Medical Association, an international journal published 48 times per year. For more information please visit the journal's homepage: