While studies have documented adverse respiratory and mental health conditions associated with direct exposure within 1 to 3 years following the event, the longer-term impact on health has been unclear.
Researchers examined the incidence of two of the most commonly reported health outcomes: asthma and posttraumatic stress (PTS) symptoms indicative of probable posttraumatic stress disorder (PTSD) among adults 5 to 6 years after the attack. They used data from the World Trade Center Health Registry, the largest post-disaster exposure registry in U.S. history, which prospectively follows a group that reported a range of WTC disaster-associated exposures on Sep. 11 and during its immediate aftermath.
Wave 1 of the study, conducted in 2003-2004, included enrollment of 71,437 adults in four groups: rescue/recovery workers, lower Manhattan residents, lower Manhattan office workers, and passersby. Sixty-eight percent of the participants completed a follow-up survey in 2006-2007. The surveys included questions regarding symptoms of asthma following Sept. 11 and event-related PTS symptoms indicative of probable PTSD.
The researchers found that overall post-event incidence among those without a prior history of asthma was 10.2 percent, with rescue/recovery workers having higher post-event asthma diagnosis rates than the next highest group, passersby on Sept. 11 (12.2 percent vs. 8.6 percent). For all eligibility groups combined, intense dust cloud exposure was associated with post-event diagnoses of asthma. Thirty-nine percent of all respondents reporting post-event diagnoses of asthma also reported intense dust cloud exposure.
“These analyses confirm that intense dust cloud exposure was associated with new asthma diagnoses for each eligibility group, including the 1,913 passersby who only had exposure to the area air and dust on September 11,” the authors wrote.
Among rescue/recovery workers, risk for asthma was highest among those who worked on the pile on Sept. 11, with risk diminishing with later start dates. Asthma risk also was independently associated with some damage to home or office, and risk was highest if there was a heavy coating of dust at home or at the office. Among residents, those who did not evacuate reported higher rates of asthma than those who did.
Of the adults without a diagnosis of PTSD before Sept. 11, 23.8 percent screened positive for PTS symptoms indicative of probable PTSD. At follow-up, the prevalence of PTS symptoms increased in every eligibility group, with the greatest increase occurring among rescue/recovery workers. At the follow-up survey, passersby had the highest levels of symptoms (23.2 percent) while residents had the lowest (16.3 percent).
Across eligibility groups, passersby had the highest prevalence of chronic PTS symptoms and office workers had the highest prevalence of resolved symptoms while rescue/recovery workers had the highest prevalence of late-onset symptoms.
With regard to mental health diagnoses, 13.6 percent of all participants previously free of PTSD reported receiving a PTSD diagnosis from a mental health professional since Sept.11; 14.0 percent reported receiving a depression diagnosis; and 7.4 percent reported receiving both. Event-related loss of spouse or job also was associated with PTS symptoms.
Co-occurrence of post-event asthma and PTS symptoms was common in the follow-up survey. Among enrollees with post-event asthma, 36 percent had PTS symptoms; among enrollees with these symptoms at follow-up, 19 percent reported a new diagnosis of asthma after Sept. 11.
“Our findings confirm that, after a terrorist attack, mental health conditions can persist if not identified and adequately treated and that a substantial number of exposed persons may develop late-onset symptoms. Our study highlights the need for surveillance, outreach, treatment, and evaluation of efforts for many years following a disaster to prevent and mitigate health consequences,” the authors concluded.
Research was completed by Robert M. Brackbill, Ph.D., MPH, of the Centers for Disease Control and Prevention, and colleagues of the New York City Department of Health and Mental Hygiene and Columbia University. The study appeared in the Aug. 5 issue of JAMA.