Helicobacter pylori infection is associated with the presence of thyroid nodules in the euthyroid population

Helicobacter pylori infection is associated with extragastric diseases. The thyroid may be one of the targets of chronic inflammation. Here, we sought to investigate whether H. pylori infections were associated with the presence of thyroid nodules. A total of 988 euthyroid subjects from China were included in this cross-sectional study. Four hundred thirty-five (44.0%) subjects were diagnosed as having thyroid nodules, and 486 (49.2%) were diagnosed with H. pylori infections. The thyroid nodules group had a higher proportion of H. pylori infections than the control group (P = 0.002). Free thyroxine (FT4) levels were lower and the prevalence of thyroid nodules was higher in patients with H. pylori infection compared to those without infection, even after adjustment for age, gender, and body mass index (BMI; all P < 0.05). The prevalence of H. pylori infection showed a decreasing trend as serum FT4 level increased (P(trend) = 0.020). Stepwise logistic regression analysis showed that H. pylori infection was significantly associated with the risk of thyroid nodules (odds ratio: 1.390, 95% confidence interval: 1.059-1.824, P = 0.018). Our results suggested that H. pylori infections were positively associated with the presence of thyroid nodules in the euthyroid population, whose thyroid functions were in the reference range.