Community-Based Study of Celiac Disease Autoimmunity Progression in Adults.

BACKGROUND & AIMS: Celiac disease can develop at any age, but outcomes of adults with positive results from serologic tests for tissue transglutaminase antibodies (tTGA) without endoscopic determination of celiac disease (called celiac autoimmunity) have not been thoroughly evaluated. We investigated the proportion of adults with celiac autoimmunity at a community medical center and their progression to celiac disease. METHODS: We analyzed waste blood samples from a community clinic from 15,551 adults for tTGA and, if titer results were above 2 U/mL, for endomysial antibody. The blood samples had been collected at 2 time points (median interval, 8.8 years) from 2006 through 2017. We collected data from the clinic on diagnoses of celiac disease based on duodenal biopsy analysis. RESULTS: Of the serum samples collected at the first time point, 15,398 had negative results for tTGA, and 153 had positive results for tTGA (>4 U/mL). Based on medical records, 6 individuals received a diagnosis of celiac disease, for a cumulative incidence of celiac disease diagnosis of 0.06% (95% confidence interval, 0.01-0.11). Forty-nine (0.32%) individuals with a negative result from the first serologic test for tTGA had a positive result from the second test. Among the 153 adults who were tTGA positive at the first time point, 31 (20%) had a subsequent diagnosis of celiac disease, 81 (53%) remained positive for tTGA without a clinical diagnosis of celiac disease, and 41 (27%) had negative test results for tTGA at the second time point. Higher initial tTGA titers, female sex, and a history of hypothyroidism and autoimmune disease were associated with increased risks of subsequent diagnosis of celiac disease. Interestingly, adults whose first blood sample had a positive test result but second blood sample had a negative result for tTGA were older, had lower-than-average initial tTGA titer results, and had a higher mean body mass index than adults whose blood samples were positive for tTGA at both time points and adults later diagnosed with celiac disease. CONCLUSIONS: In an analysis of serum samples collected from a community clinic an average of 8.8 years apart, we found that fewer than 1% of adults with negative results from an initial test for tTGA have a positive result on a second test. Of adults with positive results from the test for tTGA, only 20% are later diagnosed with celiac disease; the remaining individuals maintain persistent increases in tTGA without diagnoses of celiac disease or have negative results from second tests.

Incidence of Type 1 Diabetes Is Not Increasing in a Population-Based Cohort in Olmsted County, Minnesota, USA.

OBJECTIVES: To investigate the recent incidence of T1D in a US Midwestern county to determine whether this increase has been sustained and compare it with the incidence of celiac disease (CD) and also investigate the prevalence of CD, an associated autoimmune disease, within the cohort. PATIENTS AND METHODS: A broad search strategy was used to identify all incident cases of T1D in Olmsted County, Minnesota, between January 1, 1994, and December 31, 2010, using the Rochester Epidemiology Project. Diagnosis and residency status were confirmed through the medical record. Incidence rates were directly standardized to the 2010 US population. Poisson regression was used to test for a change in incidence rate. Clinical charts were reviewed to confirm case status. RESULTS: There were 233 incident cases of T1D. Directly adjusting for age and sex with respect to the 2010 US white population, the overall annual incidence of T1D was 9.2 (95% CI, 8.0-10.4) per 100,000 people per year among all ages and 19.9 (95% CI, 16.6-23.2) per 100,000 people per year for those younger than 20 years. There was no significant increase in the incidence of T1D over time (P=.45). Despite the overall stability in annual incidence, there was an initial increasing trend followed by a plateau. Of the 109 patients with T1D (47%) tested for CD, 12% (13) had biopsy-proven CD. CONCLUSION: The incidence of T1D has stopped increasing in Olmsted County, Minnesota, in the most recent decade. Further studies are needed to confirm this finding and explore reasons for this plateau.