Additional research shows high rate of celiac disease in adolescents and need for more evidence for screening
By Amy Ratner, Medical and Science News Analyst
Celiac disease research was frequently in the news recently, with one study showing a connection between development of celiac disease and a common virus and another between anorexia and celiac disease.
A third study found that up to 3 percent of adolescents could have celiac disease compared to 1 percent of the overall population in the United States.
Additionally, a task force that makes recommendations about preventive healthcare in the United States concluded there is not enough evidence to call for widespread screening of celiac disease in those who don’t have symptoms.
Infection with the common but otherwise harmless reovirus virus can cause the immune system to overreact to gluten and trigger development of celiac disease, according to research from the University of Chicago and the University of Pittsburgh School of Medicine.
“This study clearly shows that a virus that is not clinically symptomatic can still do bad things to the immune system and set the stage for an autoimmune disorder, and for celiac disease in particular,” said study senior author Bana Jabri, M.D., director of research at the University of Chicago Celiac Disease Center.
The study, published in the journal Science, further implicates viruses in the development of autoimmune disorders such as celiac disease and type 1 diabetes and raises the possibility that vaccines could one day be used to prevent these diseases. A vaccine to treat patients who already have celiac disease is currently under study.
For children who have the genetic background for celiac disease, getting the reovirus in the first year of life, when the immune system is still maturing can have long term consequences, according to Jabri. “That’s why we believe that once we have more studies, we may want to think about whether children at high risk of developing celiac disease should be vaccinated,” she said.
The timing of the introduction of solid foods that contain gluten and the end of breast feeding at about six months when children still have immature immune systems and are more susceptible to viruses could create the perfect storm for development of celiac disease in children with the right genes.
A study of the medical records of women in Sweden found an increased risk of association between anorexia and celiac disease both before and after a celiac disease diagnosis.
The risk also existed in the reverse, with those diagnosed with anorexia having a greater chance of being diagnosed with celiac disease, according to the study published in the journal Pediatrics.
Researchers included women who has been diagnosed with celiac disease through an intestinal biopsy from 1969 to 2008, with a median age of 28. Fifty-four of the nearly 18,000 women with celiac disease were diagnosed with anorexia compared to 180 of the nearly 90,000 matched controls. Those who had been diagnosed before they were 19 years of age were more than four times more likely to have been previously diagnosed with anorexia nervosa, an eating disorder associated with being underweight, fearing weight gain and having a distorted view of body weight. Those diagnosed at 20 years of age or older had about double the risk.
Previous research had suggested an association between the two conditions, but it was based mainly on a small number case studies compared to the extensive medical data available through Sweden’s National Patient Registry. The study concludes that attention needs to be paid to the association between the two conditions when either is diagnosed and in follow-up care.
An editorial published in the same issue of Pediatrics said the “intriguing bidirectional association could imply misdiagnosis at initial presentation, a shared genetic susceptibility, or acquired risk for one condition after diagnosing the other.”
Editorial authors Neville Golden, M.D., and Dr. K.T. Park, M.D., both of Stanford Children’s Health, wrote that both classic celiac disease and anorexia are characterized by similar gastrointestinal symptoms, including abdominal pain, diarrhea, bloating, and failure to thrive.
The authors, who were not involved in the Swedish study, also said the coexistence of eating disorders and autoimmune diseases, including celiac disease, has been well documented. The gluten-free diet, which is the only treatment for celiac disease, requires careful attention to food to eliminate the wheat, barley and rye that trigger the autoimmune response and associated symptoms. “The present study suggests that excessive focus on diet in patients with celiac disease may lead to development of anorexia nervosa in susceptible individuals,” the editorial said.
By the age of 15, slightly more than 3 percent of Denver children followed for up to 20 years had developed celiac disease, a rate about three times higher than that typically cited for the overall U.S. population, a study by researchers at the Colorado Center for Celiac Disease found.
Additionally, about 5 percent of the children in the study at one point had celiac disease autoimmunity, defined as persistence of celiac antibodies for at least three months. However, not all children who have a period of celiac disease autoimmunity go on to develop celiac disease, the study, published in the journal Gastroenterology, found. In nearly half, the antibodies stop showing up without treatment.
The study, conducted by Edwin Liu, M.D., director of the celiac center, and colleagues, followed about 1,300 children with genetic risk factors for celiac disease, 66 of whom developed celiac disease and 46 who only developed celiac autoimmunity. The study “shows continuing development of celiac disease throughout early childhood,” the study authors wrote. “By 15 years of age, an estimated 3.1 percent of the Denver population develops celiac disease and an additional 2 percent develops a lesser degree of celiac disease autoimmunity.”
The study notes this cumulative incidence of celiac disease is the highest to date in North America and is consistent with the prevalence reported in Sweden for 12-year-olds born during an “epidemic” thought to be due to early introduction of large amounts of gluten in the infant diet.
The study suggests that the marked increase in celiac disease found in the study “may be a new phenomenon that has affected this current generation of youth.” Dr. Liu said he is not sure why this new generation is different. “It does beg the question as to whether or not there are new environmental triggers for celiac disease that our population faces now, compared to before,” he said, noting that it is possible there is something unique to Colorado. “But we just don’t know.”
Dr. Liu said it’s also not clear why the celiac autoimmunity does not always lead to celiac disease or why the antibodies are transient. Large scale studies are needed to find the triggers and factors related to their spontaneous resolution, he noted. “I speculate that it may not take much, relatively, to trigger autoimmunity in an at-risk individual, but likely requires ongoing or secondary factors to continue to push it towards full blown celiac disease,” Liu said.
The study results may also have implications for screening to detect celiac disease. “It might be argued that more aggressive screening during early childhood would be indicated for the first 5 to 10 years, followed by less frequent testing thereafter,” the authors wrote.
Screening was also in the news because the US Preventive Health Services Task Force (USPSTF) recently concluded there is not enough evidence to support screening for celiac disease in those who don’t have symptoms.
In a report and review published the Journal of the American Medical Association the task force said more research, including population-based studies, are need to assess the value of screening in the general population in the United States. More research is also needed before the task force can recommend screening of targeted populations at increased risk, including those with family members who have celiac disease and those with other autoimmune conditions.
“It is critical that the USPSTF statement be interpreted correctly,” said Alice Bast, CEO of Beyond Celiac. “People at increased risk because relatives have been diagnosed or with symptoms should strongly consider being tested. Waiting until definitive research is available to assess any benefits of screening can result in undiagnosed patients suffering needlessly.”
The task force based its recommendations on review of randomized clinical trials and cohort or case-control studies on clinical benefits and harms of screening versus no screening for celiac disease or treatment versus no treatment for screen-detected celiac disease and studies on diagnostic accuracy of serologic tests for celiac disease.
“Although some evidence was found regarding diagnostic accuracy of tests for celiac disease, little or no evidence was identified to inform most of the key questions related to benefits and harms of screening for celiac disease in asymptomatic individuals,” the task force concluded. “More research is needed to understand the effectiveness of screening and treatment for celiac disease, accuracy of screening tests in asymptomatic persons, and optimal screening strategies.”
Leaders of Beyond Celiac agree with the Task Force that more research, including population-based studies, are needed to assess the value of screening the in the general US population, and in targeted populations at increased risk such as those with family members who have celiac disease and those with other autoimmune disorders. That research will then provide the Task Force with the evidence it needs to say definitively in what situations screening would – or would not – be valuable.
In the absence of that research, it is important to continue diagnosing people with celiac disease. Not only will patients and their families benefit, but their healthcare providers, employers and health insurers will benefit as well. People who have been diagnosed and who then avoid gluten, improve the quality of their health, their life and their ability to study or work. They lower their chances of suffering from other serious disease complications, including miscarriage, osteoporosis, malnutrition and cancer.
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