Celiac-related Antibody Profiles and Glycemic Control in Iraqi Children and Adolescents With Type 1 Diabetes: A Cross-Sectional Study

Abstract

Background: Celiac disease is associated with type 1 diabetes mellitus (T1DM), but differences in continuous antibody concentrations do not establish celiac disease. This study compared celiac-related antibody profiles between Iraqi children with T1DM and healthy controls and examined associations with glycemic control. Methods: A cross-sectional study in Baghdad, conducted from 2 June 2025 to 15 January 2026, included 60 participants with T1DM and 40 controls aged 2–15 years. Total immunoglobulin A (IgA), tissue transglutaminase antibodies (tTG-IgA/IgG), and deamidated gliadin peptide antibodies (DGP-IgA/IgG) were compared using Mann–Whitney tests. Log-linear regression with HC3 robust standard errors estimated covariate-adjusted geometric mean ratios (GMRs). Holm correction addressed multiple comparisons. HbA1c–antibody associations were assessed within the T1DM group. Results: Median total IgA was higher in T1DM than controls (137.00 vs 109.00 mg/dL), whereas tTG-IgA (0.99 vs 2.33 U/mL) and DGP-IgG (0.88 vs 1.39 reported units) were lower; all three comparisons remained significant after Holm correction. Adjusted GMRs were 1.31 (95% CI 1.15–1.48) for total IgA, 0.48 (0.36–0.65) for tTG-IgA, and 0.51 (0.35–0.75) for DGP-IgG. Differences in tTG-IgG and DGP-IgA were not statistically significant. Within T1DM, no HbA1c–antibody association was supported after covariate adjustment and multiplicity correction. Conclusions: The groups differed in total IgA, tTG-IgA, and DGP-IgG concentrations without evidence of an association between HbA1c and antibody levels. Missing assay thresholds and confirmatory celiac diagnoses preclude estimating celiac prevalence or diagnostic accuracy. The unexpected antibody pattern requires laboratory and source-record verification.