The study, published online Nov. 8 in the American Journal of Industrial Medicine, reveals that exposure to the toxic dust from the towers’ collapse has sent 9/11 first responders’ asthma rates soaring. While previous studies have linked increased asthma in ground zero responders, this is the first time 9/11 responders’ asthma rates have been compared to the general population.

“This epidemic of asthma among WTC responders started right after the 9/11 disaster and we are still observing elevated rates of asthma in this population. It is critical to keep monitoring responders’ health and provide proper treatment,” said Hyun Kim, M.D., first author, epidemiologist and assistant professor of population health at the North Shore-LIJ Health System the Hofstra North Shore-LIJ School of Medicine.

Researchers studied 20,834 responders who received medical screenings from July 2002 to December 2007 at the WTC Medical Monitoring and Treatment Program and compared the results with the U.S. National Health Survey Interviews sample data for the years 2000 and 2002-2007.

Eighty-six percent of these WTC responders were men, and the average duration of work at the WTC sites was 80 days. Forty-two percent of study participants were uniformed and other law enforcement and protective service workers. Other responders were construction workers and installation, maintenance and repair workers, along with transportation and material moving workers who helped with restoration, debris removal and/or cleanup efforts at the site.

The researchers found that 6.3 percent of WTC responders reported asthma symptoms or attacks in the last year, compared to only 3.7 percent of the U.S. general population. And while the general population’s asthma rates remained stable during the entire period, WTC responders experienced large increases in 12-month asthma rates from 2000 to 2005.

When comparing asthma rates of WTC responders in 2000 (1 year before 9/11) to 2005, the 12-month asthma rate increased by 40 times. Furthermore, when comparing 2002 (1 year after 9/11) to 2005, the 12-month asthma rate doubled among WTC responders.

“…[T]he results show that WTC responders have higher rates of asthma than the general population,” said Jacqueline Moline, M.D., vice president and chair of the Department of Population Health at North Shore-LIJ Health System and the Hofstra North Shore-LIJ School of Medicine, and director of the Queens WTC Clinical Center of Excellence at Long Island Jewish Medical Center/Queens College. “This reinforces the fact that continued surveillance is critical to avoid permanent lung damage and other irreversible illnesses among the WTC responder population.”

Preliminary study results were previously presented in CHEST in 2009.