By Amanda Gardner
WEDNESDAY, September 7, 2011 (Health.com) — People exposed to the terror and dust of the 2001 attacks on the World Trade Center have higher rates of asthma and post-traumatic stress than those who were further away from Ground Zero. But they also have high rates of a less obvious health problem: heartburn.
A new study of more than 37,000 adults who worked at Ground Zero or lived near the site found that one-fifth experienced heartburn, indigestion, or acid reflux for the first time ever in the three years following the 9/11 attacks. Five to six years after the disaster, 13% were still experiencing these common symptoms of gastroesophageal reflux disease, or GERD.
The rates were even higher among rescue and recovery workers: One-third reported the onset of GERD-like symptoms by 2004, and one-quarter still had symptoms up to three years later.
The findings come as no surprise, since acid reflux—the seepage of stomach acids and other contents into the esophagus—frequently occurs side by side with asthma or stress, including post-traumatic stress disorder (PTSD).
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"Even relatively minor stress can produce slow stomach emptying," says Charlene Prather, MD, a professor of gastroenterology at the Saint Louis University School of Medicine, in Missouri. "And if the stomach isn't emptying properly, then there are more materials that can reflux into the esophagus."
A 2005 study in the Journal of Psychosomatic Research found that people with chronic heartburn and acid reflux who were asked to deliver a five-minute speech in front of an audience experienced an acute worsening of their symptoms, unlike a group with identical preexisting symptoms and acid levels that did not have to speak.
If the fleeting butterflies that come with public speaking can trigger acid reflux, it stands to reason that the persistent stress of PTSD can affect the gut as well.
And sure enough, in the new study, rescue workers and people who lived or worked in the vicinity of the World Trade Center were at higher risk of acid reflux if they also had PTSD, a type of anxiety disorder. By 2006 or 2007, just under one-quarter of the study participants who had PTSD were experiencing acid reflux symptoms, compared to 8% of those who had neither PTSD nor asthma.
Next page: Serotonin may play a role
The brain chemical serotonin, which is believed to play a role in depression and anxiety disorders, is also "richly involved in the gut," Dr. Prather says. Serotonin contributes to our physical perceptions of our stomach and digestive system, and it also helps control how things move through our digestive tract.
"The gastrointestinal tract has a nervous system that's similar in complexity to what is present in the brain," Dr. Prather says. "There are as many nerves in the gut as there are in the spinal cord."
Stress-related behaviors may be involved as well, however. People who are stressed out are more apt to smoke, overeat, and drink alcohol, all of which can make acid reflux more likely by relaxing or putting pressure on the esophageal sphincter, which connects the stomach to the esophagus, Dr. Prather explains.
Stress isn't the only culprit involved in post-9/11 acid reflux. The study authors suspect that the toxic Ground Zero dust may be responsible as well.
The smoldering wreckage of the Twin Towers contained large amounts of alkaline cement dust, which long before 9/11 had been linked to asthma and indigestion in cement factory workers and others exposed to the dust in workplace settings.
As with PTSD, the likelihood of experiencing acid reflux symptoms was highest among the study participants with the most exposure to the dust. Thirty-one percent of the people who experienced "intense" dust exposure while working at the wreckage site reported symptoms by 2004, compared to 19% of the workers who had no exposure to the dust—a pattern that persisted three years later.
The study "does raise questions about whether or not the very toxic alkaline exposure associated with the dust pile may in some way have altered the physiological function or sensation of the esophagus or lower esophageal sphincter," says William Chey, MD, a professor of gastroenterology at the University of Michigan Medical School, in Ann Arbor, and a co-editor of the American Journal of Gastroenterology, which published the new study.
All of the men and women included in the study are part of the World Trade Center Health Registry, a database of people exposed to the 2001 attacks and the immediate aftermath. The registry is led by the New York City Department of Health and Mental Hygiene and is funded by the National Institute of Occupational Safety and Health.