By age 15 years, 3.1% of adolescents in Denver developed celiac disease, and another 2% developed a lesser degree of celiac disease autoimmunity, according to a 20-year prospective longitudinal study.
“Although more than 5% of children may experience a period of celiac disease autoimmunity [CDA], not all develop celiac disease [CD] or require gluten-free diets,” Edwin Liu, MD, of University of Colorado School of Medicine and Children’s Hospital Colorado (Aurora, Colo.), wrote with his associates in the May issue of Gastroenterology (doi: 10.1053/j.gastro.2017.02.002). Most celiac autoimmunity probably develops before age 10, “which informs future efforts for universal screening,” they added.
About 40% of the general population has the HLA-DQ2 or DQ8 risk genotypes for celiac disease [CD], but little is known about rates of celiac disease among children in the United States, the researchers said. To help fill this gap, they analyzed celiac-risk HLA genotypes for 31,766 infants born between 1993 and 2004 from the Diabetes Autoimmunity Study in the Young. The 1,339 children with HLA risk genotypes were followed for up to 20 years.
By age 15 years, 66 of these children (4.9%) had developed tissue transglutaminase autoantibodies (tTGA) consistent with CDA, and also met criteria for CD, the researchers said. Another 46 (3.4%) children developed only CDA, of whom 46% experienced spontaneous resolution of tTGA seropositivity without treatment. By using genotype-specific risk weighting for population frequencies of HLA, the researchers estimated that 2.4% of the general population of Denver had CDA by age 5 years, 4.3% had CDA by age 10 years, and 5.1% had CDA by age 15 years. Estimated rates of CD were 1.6%, 2.8%, and 3.1%, respectively.
These findings suggest a significant rise in the incidence of CD compared with historical estimates in the United States, and reflect recent studies “using different approaches in North America,” the researchers said. Reasons for the “dramatic increase” are unknown, but environmental causes seem likely, especially given the absence of identified genetic differences and marked changes in the prevalence of CD during the past 2 decades, they added.
Several other reports have documented fluctuating and transient tTGA antibodies in children, the researchers noted. Awareness of transient CD autoantibodies might limit public acceptance of universal screening programs for CD, they said. “Continued long-term follow-up will identify whether the autoimmunity in these subjects truly abates and tolerance develops, or if CDA will recur in time, possibly in response to additional stimulating events,” they added. “At present, low positive tTGA results should be interpreted with caution, and do not necessarily indicate need for biopsy or for treatment.”
The study did not include the DR5/DR7 risk genotype, which accounts for less than 5% of CD cases. The study also did not account for the estimated 2.5% of the general population that has DR3/DR7, which can be considered high risk, the researchers said. Thus, the study is conservative and might underestimate the real incidence of CD or CDA, they added.
The National Institutes of Health provided funding. The investigators reported having no conflicts of interest.