Celiac disease is an autoimmune disorder that damages the small intestine when gluten, a protein found in wheat, barley and rye, is ingested. According to a recent study published in The American Journal of Gastroenterology, the worldwide incidence rate among children is “extremely high,” but varies by region.
This research was part of The Environmental Determinants of Diabetes in the Young (TEDDY), an international study that followed a cohort of children who have a genetic risk for developing celiac disease and/or type 1 diabetes mellitus. The study covered different regions in the U.S. and Europe, including Colorado, Washington, Georgia, Sweden, Finland and Germany. Children in Colorado showed the highest risk for celiac disease among the U.S. sites.
“The centers were chosen where there was a strong expertise in celiac disease,” said Marisa Stahl, MD, an assistant professor of pediatrics at the University of Colorado School of Medicine and a lead researcher on the study. “There is a wealth of experience here in Colorado, especially in terms of running a cohort study.”
The children were screened at birth for specific HLA genes, which are known to be necessary for celiac disease development. Over the course of 15 years, researchers monitored them by collecting blood samples and testing them for elevated antibodies that are associated with celiac disease autoimmunity.
“The children are essentially under the microscope for the first 15 years of their life to try to help us understand the causes of these diseases,” said Stahl, a pediatric gastroenterologist at Children’s Hospital Colorado. “The families definitely make a sacrifice to be in the study, and we’re very appreciative of that.”
‘Celiac disease is more common than we thought’
The researchers aimed to calculate the true incidence of celiac disease worldwide. Previously, incidence rates had been estimated based on the presentation of symptoms. However, Stahl noted that this approach “can really miss a lot of people due to high rates of undetected diseases.”
Therefore, the researchers chose to follow the children from birth, regardless of their symptoms, and track when they first develop celiac disease. The incidence rate in this enriched cohort was then used to determine the rate for the general population. This approach allowed TEDDY to make a more unbiased estimate.
Stahl and colleagues found that incidence rates were high, and they varied by region, ranging from 0.9% in Washington to 3.0% in Sweden.
“That’s higher than what’s been estimated, especially in the U.S.,” Stahl said. “Celiac disease is more common than we thought it was.”
The study also showed that children in Colorado have a 2.5-fold higher risk of celiac disease compared to Washington. According to Stahl, among the U.S. cities studied, “Colorado conferred the highest risk” at 2.4%. Likewise, Swedish children had a 1.4-fold and 1.8-fold higher risk of celiac disease compared to children in Finland and Germany, respectively.
Regarding the regional differences, she said, “There are clearly factors other than HLA that are driving celiac disease risk. There may be other genetic factors or environmental factors, or it may actually be an interplay of the environment and genes in epigenetics.”
These outside factors may include diet, chemical exposures, vaccination patterns or gastrointestinal infections, which TEDDY has already been investigating.
“The next steps for TEDDY will be incorporating what we know about these different risk factors and figuring out how we put them together to better understand who is at risk of developing celiac disease,” Stahl said.
Screening for celiac disease in the future
Celiac disease is currently screened using genetic and simple antibody tests but only when individuals have symptoms or if the disease runs in the family.
However, Stahl noted that children may be missed if they do not present with classic symptoms. Given the high incidence rates in certain regions, clinicians may need to lower the threshold for screening.
“The TEDDY study helps lend evidence that (mass screening efforts) may be helpful,” she said. “In the future, there may be an approach where, similar to how we screen for high lipid levels at the pediatrician, we may start just screening for celiac disease.”
Guest contributor: Brittany Truong is a freelance writer specializing in health and science.