Endocrine Abstracts

Aim: Patients with autoimmune thyroid disease (AITD) or type 1 diabetes (T1DM) are prone to develop other autoimmune diseases. This has led to the concept of autoimmune polyglandular syndromes (APS). It has been proposed that AITD and type 1 diabetes are both part of the same APS (subtype 2). This would imply that they associate with the same diseases. We evaluated whether the clustering of autoimmune antibodies differs between AITD and T1DM.

Methods: Anti-thyroid peroxidase antibodies (anti-TPO), parietal cell antibodies (PCA), intrinsic factor antibodies (IF), celiac antibodies and anti-adrenal antibodies (AA) were assessed in 853 AITD patients, 658 type 1 diabetes patients, and 102 patients affected by both entities.

Results: Prevalences of PCA and AA antibodies were significantly increased in patients affected by both AITD and T1DM, compared to those with either AITD or type 1 diabetes (P<0.05). However, celiac antibodies did not associate with thyroid autoimmunity (i.e. anti-TPO or AITD) in the type 1 diabetes group (OR 0.34, 95% CI 0.08–1.5). In AITD patients, having PCA was associated with celiac antibodies (OR 4.8, 95% CI 1.1–21.9) and with adrenal antibodies (OR 7.0, 95% CI 2.0–24.5). In contrast, in type 1 diabetes, associations between PCA with AA (OR 2.4, 95% CI 0.7–8.6) or with celiac antibodies (OR 0.28, 95% CI 0.04–2.2) were not significant. The same analyses including IF antibodies led to same conclusions.

Conclusion: Autoimmune thyroid disease shows clustering of gastric autoimmunity with celiac and adrenal autoimmunity, which is consistent with the proposed entity of the autoimmune polyglandular syndrome type 2. The finding that such clustering is not seen in type 1 diabetes suggests that type 1 diabetes and thyroid autoimmunity may be part of different subtypes of autoimmune polyglandular syndromes.