Correlation of Autoimmune Thyroid Diseases With Helicobacter pylori Infection

Autoimmune thyroid diseases are multifactorial conditions caused by genetic and environmental factors. Among environmental factors, infectious agents include viruses, bacteria, and parasites acting as triggers. The current study intended to investigate the association between Helicobacter pylori infection and autoimmune thyroid diseases in a group of Iranian cases with Hashimoto's thyroiditis (HT) and Graves' disease (GD). This study included adult cases newly diagnosed with GD and HT and euthyroid controls. A number of clinical and biochemical factors were evaluated, including tests of thyroid function and serum Helicobacter Ab (IgG), and then inter-group comparisons were performed. Data from 404 patients with HT and 248 cases with GD were analyzed. Also, data from 480 healthy controls were analyzed. For those with HT, GD, and controls, the prevalence of Helicobacter pylori infection was 93.3%, 92.7%, and 88.8%, respectively. The prevalence of H. pylori infection in cases with HT and GD was significantly higher compared to controls. While concerning the prevalence of H. pylori infection, the two groups (HT and GD) were not significantly different. H. pylori antibody level was significantly correlated with FT4, FT3, Anti-TPO, and Anti-Tg in cases with HT. In the group of patients with GD, the H. pylori antibody had a significant positive correlation with Anti-TPO and Anti-Tg. According to the present results, H. pylori is associated with autoimmune thyroid diseases (both Hashimoto's and Graves' diseases).