Two hallmark health problems of World Trade Center responders -- post-traumatic stress disorder and respiratory symptoms -- are linked, and one illness may be heightening the effect of the other, Stony Brook researchers have found.
In a study of 8,508 police officers who worked at the World Trade Center site and 12,333 "nontraditional" responders, researchers looked at the incidence of PTSD, respiratory symptoms and lung function.
Their findings, published online last month in the journal Psychological Medicine, confirmed what others have found: Statistically, PTSD and respiratory symptoms were "moderately" interrelated in both groups.
"This shows the important interaction between mental and physical health, and how they complicate one another," said lead author Dr. Benjamin Luft, a Stony Brook professor and medical director of the Long Island World Trade Center Medical Monitoring and Treatment Program.
That interaction, he said, is a reason for ensuring that health care doesn't artificially separate the two.
Using statistical models, the researchers also found that PTSD appeared to contributing to the persistence of respiratory symptoms.
"The study reaffirms what has been shown, but it takes the question to the next level. What appears to be driving what?" said another researcher, Evelyn Bromet, a professor in the Department of Psychiatry and Behavioral Science and Preventive Medicine at Stony Brook.
The study suggests that PTSD is driving the respiratory symptoms, Bromet said -- a finding researchers hope to confirm in another study already under way.
The latest study, which used data collected between 2002 and 2008, found that a lower percentage of police had PTSD -- 5.9 percent, compared with 23 percent of civilian responders. Police also had a lower rate of respiratory symptoms -- 22.5 percent, versus 28.4 percent.
Luft speculated that officers' training and experience may better prepare them for dealing with trauma, or the kind of person who chooses to be an officer may be psychologically better equipped to begin with.
Another possibility is that police underreport their PTSD symptoms because they fear it will hurt their careers, he said.
Michael Von Korff, a Seattle-based researcher who studies relationships between psychological and physical illness, said the study underscores "that physical symptoms and psychological symptoms tend to run together. We don't fully understand the mechanism of that," he said.