According to researchers, adults 20 and older who had been previously diagnosed with celiac disease are twice as likely to develop anorexia later in life, while those under the age of 19 are 4.5 times more likely to have also been previously diagnosed with anorexia.
“This intriguing bidirectional association could imply misdiagnosis at initial presentation, a shared genetic susceptibility, or acquired risk for one condition after diagnosing the other,” co-authors Neville Golden and K.T. Park write in a commentary accompanying their study.
The observational study looked at two groups of women: about 18,000 who had celiac disease and over 89,000 who did not. They were followed for 1,174,401 person-years (a measurement often used in health studies to calculate incidence rates of an illness, Medical News Today says).
Researchers found that 54 of the patients with celiac disease had received a diagnosis of anorexia nervosa – that’s compared with 180 of their age-matched counterparts in the group without celiac disease.
That is an incidence rate of anorexia after a celiac disease diagnosis of 27/100,000 person-years.
They also found that some patients had a record of anorexia before being diagnosed with celiac disease (33 participants with celiac disease and 76 without).
Another important finding from the study was the fact that misdiagnosis or delayed treatment of celiac disease can happen during the teen years, which is a particularly vulnerable time for growth and development.
Researchers were not able to say why that is, but speculate that it may be that people with celiac disease were initially misdiagnosed with anorexia nervosa, or vise versa.
“Both classic [celiac disease] and [anorexia nervosa] are characterized by similar gastrointestinal symptoms, including abdominal pain, diarrhea, bloating and failure to thrive,” the authors say. “Misdiagnosis can be devastating, potentially compounding the injurious longstanding effects of treatment delay for either diagnosis and leading to progressive bone disease, possibly early mortality, and overall poor quality of life.”
The study was published in the journal Pediatrics.
A separate study released recently suggests that a common virus may be the root cause of celiac disease.
According to researchers from University of Chicago Celiac Disease Center, reovirus – a harmless virus that doesn’t normally make people sick – could trigger a person’s immune system to overreact to gluten, which can then lead to a diagnosis of celiac disease.
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“This is the first study to show that a virus can change the way our diet is seen by the immune system,” senior author Dr. Bana Jabri told NBC News.
Researchers say the virus shuts down the body’s “peacekeeper” response to gluten and tricks the immune system into thinking gluten is harmful.
In their study, Jabri and his team found that patients with celiac disease tended to have more antibodies to reoviruses in their blood compared to their healthy counterparts. Those with these antibodies were also found to have more of the inflammation associated with celiac disease.
According to Dr. Peter Green, director of the Celiac Center at New York-Presbyterian/Columbia University Medical Center, about 40 per cent of people have the genes that predispose them to celiac disease. However, only one per cent end up actually developing the disorder, he tells NBC News.
“This study demonstrates the mechanism that a viral infection can cause a switch in the immune system that results in the development of food intolerance,” he says.
These findings, Jabri says, can now help researchers find new ways to treat and prevent celiac disease.
According to the Canadian Digestive Health Foundation, it’s believed that more than 330,000 Canadians have celiac disease but only about 110,000 are actually diagnosed.
It takes an average of one year to get a diagnosis of celiac disease from the first recognizable onset of symptoms but can take as long as 12 years in some cases.