May 20, 2008 -- Most Americans who have celiac disease probably don't know it.
A new study shows that the criteria used to diagnose the disorder may be too stringent, leaving many people undiagnosed and untreated.
It is estimated that one in every 100 Americans may be affected by celiac disease. But "only 5% of these people have ever been diagnosed," says Peter H. Green, MD, professor of clinical medicine at Columbia University Medical School in New York City.
Green moderated a news briefing to discuss the new research at Digestive Disease Week 2008 in San Diego.
Also at the briefing, researchers reported early success in developing new treatments for celiac disease.
What Is Celiac Disease?
People with celiac disease cannot tolerate gluten protein found in wheat, rye, and barley products, such as many breads and cereals. They must follow a strict gluten-free diet to control their symptoms, which can include diarrhea, weight loss, abdominal pain, anemia, and oral ulcerations.
When people with celiac disease eat foods containing gluten, their immune system attacks the protein. This damages the intestinal lining, hampering the ability to absorb vital nutrients from food and eventually leading to malnutrition.
Currently, a biopsy of the small intestine is considered the gold standard for diagnosing celiac disease, Green says. Doctors look for damage of the villi -- little finger-like protrusions in the small intestine important for absorbing nutrients.
The biopsy is typically given if blood tests show you have certain antibodies that are associated with celiac disease.
Biopsy May Miss Celiac Disease
The new study involved 145 patients suspected of having celiac disease. Of those, 71 were positive on the antibody blood test. Of those, 48 met the criteria for celiac disease on biopsy.
The remaining 23 patients were divided randomly into two groups. One group was placed on a gluten-free diet, and the other continued eating a regular diet that included gluten.
After one year, patients on the gluten-free diet were free of symptoms.
But symptoms worsened in people who continued to eat the regular diet. And their intestinal linings showed signs of inflammation and deterioration.
The fact that they got worse shows they had celiac disease, says researcher Markku Maki, MD, professor of pediatrics at the University of Tampere in Finland.
Plus, when these patients then eliminated gluten from their diet, their symptoms got better and their intestinal lining healed, he tells WebMD.
Green says researchers are working on a better blood test to detect celiac disease.
There are other reasons celiac disease is often missed, he adds. "It's a problem of physician education, as doctors are taught it's a rare childhood disease," he says. In fact, celiac disease can appear at any point in life.
Then, there's the fact that the symptoms are so varied. Patients may go to one doctor for bloating and diarrhea, another for joint pain, and another for unexplained anemia, and no one puts all the pieces of the puzzle together, Green says.
New Pill for Celiac Disease
Once celiac disease is diagnosed, "the only effective treatment is a lifelong gluten-free diet. But gluten is so ubiquitous that it is difficult to completely get it out of the diet," Green says.
Inadvertent consumption of gluten is the major causes of symptoms in people who know they have the disease, he says.
That's why researchers are closely watching early studies of two new treatments that may help protect patients with celiac disease from exposure to gluten.
The first study looked at an experimental pill called larazotide, also known as AT-1001. It blocks gluten from crossing into the intestinal lining where it can cause harm.
The study of 69 patients showed that those who were given gluten and larazotide had less nausea, bloating, and other symptoms of celiac disease than those who were given gluten and a placebo. However, the drug did no better than placebo at preventing gluten from leaking through the intestine lining over the 14 days of active treatment, which was the study's primary goal.
"What was surprising was that leakage improved in all patients over the first week," says Daniel Leffler, MD, clinical research director at the Celiac Disease Center at Beth Israel Deaconess Medical Center in Boston.
"It shows that just being in a study helps people practice healthier habits and improves outcomes," he tells WebMD.
Also, there were some signs that the drug helped to curb gluten leakage in the weeks after treatment ended, "suggesting the drug has some efficacy," he says.
"The results are somewhat promising," Leffler says, adding that the researchers are proceeding with a larger, longer trial.
The study was funded by Alba Therapeutics, maker of the drug.
Yet another treatment that shows promise is a pill that contains two enzymes engineered to digest gluten, Green says.
The very fact that the pharmaceutical industry is becoming interested in celiac disease is "exciting for patients," he says. "Probably one of the reasons that condition is so underdiagnosed is because there is no medication and doctors aren't being educated."