Association of Helicobacter pylori Infection with Papillary Thyroid Carcinoma: A Case-control Study

Abstract

Background: The thyroid nodules incidence has risen worldwide. Although factors such as increasing the use of imaging techniques and more rapid detection of small thyroid nodules have been implicated in the recent rise in thyroid cancer incidence, some environmental parameters such as infectious agents may be involved. Helicobacter pylori infection is an environmental risk factor, which may mimic the antigenic properties of membranes of thyrocytes. Objectives: This study aimed at evaluating the association of H. pylori infection with benign and malignant thyroid nodules in comparison with the control group. Methods: Patients with benign thyroid nodules, papillary thyroid cancer (PTC), and euthyroid healthy controls without thyroid nodules that had just been diagnosed were included in the study. All participants underwent clinical examination. Various biochemical parameters such as serum H. pylori Ab (IgG) and thyroid function tests were measured. Comparisons were made between groups. Results: Finally, 370 patients with benign thyroid nodules, 364 patients with PTC, and 360 healthy subjects without nodules participated as a control group. In the patients with PTC, the prevalence of H. pylori infection was 89.6%, while in the group of patients with benign thyroid nodules and the control group was 81.1% and 75%, respectively (P < 0.001). Helicobacter pylori antibody (Ab) titer was not significantly associated with any of the anthropometric and biochemical variables. Conclusions: Helicobacter pylori infection was significantly higher in patients with benign thyroid nodules and PTC than in the control group. Also, the rate of infection was significantly higher in the malignant nodule group than in the benign thyroid nodules group.