Vietnam Vets Study Links Asthma and PTSD

Vietnam Vets Study Links Asthma and PTSD
THURSDAY, Nov. 15 (HealthDay News) -- A study of male twins who servedin Vietnam has uncovered a strong link between asthma and post-traumaticstress disorder (PTSD).
Columbia University researchers, reporting in the Nov. 15 issue of theAmerican Journal of Respiratory and Critical Care Medicine, foundthat those who suffered the most from PTSD were more than twice as likelyto have asthma.
"This is very good data," said Keith A. Young, co-director of theCentral Texas Veterans Health Care System Neuropsychiatry ResearchProgram. "One of the things that is very clearly delineated by this studyis that there truly is an association. This association has been seen withother anxiety disorders before, and there were some hints with PTSD, butthis is the best. This kind of sets it in stone."
The challenge now is to find out whether this is a cause-and-effectrelationship.
Previous studies have indicated a more general link between anxietydisorders and asthma, but this study focused specifically on PTSD, adisorder that involves nightmares, flashbacks and panic attacks linked to"triggers" that develop after exposure to combat or other extremelydisturbing events.
This study looked at 3,065 male twin pairs listed in the Vietnam EraTwin Registry.
The twins were either identical (meaning they shared all the samegenetic material) or fraternal (sharing only half their genetic material).Such twin studies are useful to science, because they can help tease outgenetic and environmental influences.
The twins in this study had all lived together as children and had allserved on active military duty in Vietnam. There were no significantdifferences in history of combat exposure or cigarette smoking. Theoverall prevalence of asthma was 6 percent and was about the same inidentical and fraternal twins.
Twins who suffered from the most PTSD symptoms were 2.3 times morelikely to have asthma when compared with those who suffered from the leastPTSD symptoms. The increased risk was about the same for both fraternaland identical twins, suggesting an environmental underpinning rather thana genetic one.
"If there had been a strong genetic component to the link betweenasthma and PTSD, the results between these two types of twins would havebeen different, but we didn't find any substantial differences between thetwo," lead researcher Renee D. Goodwin, an assistant professor ofepidemiology at the Mailman School of Public Health at Columbia Universityin New York City, said in a statement.
No one knows what the mechanisms are behind the association. It'spossible that some sort of traumatic stress could trigger both PTSD andasthma, or one condition could contribute to the other.
"In my mind, the most likely thing that would relate these two ischildhood stress," Young said. "It's very well-known that children who area under a lot of stresses can grow up to have a different mental healthoutcome than their twin."
According to the study authors, understanding the association bettermay help PTSD prevention efforts by suggesting ways to modifyenvironmental risk factors.