Both celiac disease and related celiac disease autoimmunity are rising and rates vary by geographic location
By Amy Ratner, Medical and Science News Analyst
Both celiac disease and celiac disease autoimmunity are likely underdiagnosed in the general population, according to an international study presented at Digestive Disease Week (DDW).
Researchers working on The Environmental Determinants of Diabetes in the Young (TEDDY) study set out to provide more current estimates of the incidence of celiac disease in children at genetic risk selected from the general population.
They hypothesized that the frequency of the genes that are a major risk factor for development of celiac disease could be used to estimate the regional incidence of celiac disease in countries and states participating in TEDDY.
TEDDY – The Environmental Determinants of Diabetes in the Young (TEDDY) is a multinational study that follows children at high genetic risk for type 1 diabetes, with the development of celiac disease as a secondary outcome.
“The study shows that incidence is still rising and there is variability based on the sites,” said Marisa Gallant, M.D., the study author who detailed results in a poster presented at DDW, the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. She noted that differences in genetic make-up or something in the environment might account for the variations, though more research is needed.
Researchers found variability between four countries and among three U.S. states – Colorado, Washington and Georgia.
Sweden had the highest 10-year cumulative incidence of both celiac disease, with an estimate of 2.1 percent, compared to 1.8 percent in Finland and Germany and the United States. Celiac disease was defined as having been biopsy proven or by initially having two, consecutive highly positive tissue transglutaminase antibody tests.
Previous studies have shown that celiac disease occurs in about 1 percent of the population.
The study also looked at 10-year estimates of celiac disease autoimmunity, which was defined having two consecutive positive (tTG) tests. Not everyone who has celiac disease autoimmunity will develop celiac disease, the study notes. Sweden also had the highest cumulative incidence of celiac disease autoimmunity, at 6.8 percent, compare to 5.9 percent in Finland and Germany and 5 percent in the United States.
When researchers looked at individuals states in the study, they found that Colorado had the highest 10- year estimates for both celiac disease and celiac disease autoimmunity, 2.3 percent and 7.6 percent. Meanwhile, Georgia had rates of 1 percent and 5.4 percent and Washington, 1.2 percent and 5.7 percent. The study notes that this variation in prevalence needs further investigation.
The study was based on nearly 7,000 at-risk children followed from birth in TEDDY who are screened annually for tTG, the antibody commonly used to diagnose celiac disease along with an intestinal biopsy. Of these children, 456 were found to have celiac disease and 1,228 to have celiac disease autoimmunity.
National bone marrow registries were then used to determine the frequency with which the HLA genes associated with celiac disease risk occurred in each country participating in the study. Data on cumulative risk was then used to calculate the estimated cumulative incidence by country.
“The cumulative incidence of [celiac disease] and [celiac disease autoimmunity] within the general population in the [United States] is greater than past estimates, the study concluded. The study was also published in the journal, Gastronenterology, in May.