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.