Helicobacter pylori Seroprevalence and Its Associations with Sociodemographic Characteristics, Environmental Factors, and Gastrointestinal Complaints: A Cross-Sectional Study in the Adult Population of Kaunas City, Lithuania

<i>Background and Objectives</i>: <i>Helicobacter pylori</i>, classified as a Group I carcinogen, is the main risk factor for gastric cancer, one of the leading causes of cancer mortality globally. Lithuania reports one of the highest gastric cancer rates in Europe, yet recent large-scale epidemiological data on <i>H. pylori</i> prevalence are lacking. This study aimed to assess the current seroprevalence of <i>H. pylori</i> in Lithuanian adults and its associations with sociodemographic, environmental factors, and dyspeptic symptoms. <i>Materials and Methods</i>: A cross-sectional study was conducted between 2020 and 2023 at the Lithuanian University of Health Sciences in Kaunas city. Randomly selected adults aged 25-69 years underwent venous blood sampling for <i>H. pylori</i> IgG antibody testing (Serion ELISA) and completed a questionnaire on demographic-environmental factors and dyspeptic symptoms in the past 30 days. Subjects previously treated for <i>H. pylori</i> were excluded from seroprevalence analysis. Seroprevalence was compared across age groups using χ² and Z-tests with Bonferroni correction. Multivariable logistic regression identified factors associated with <i>H. pylori</i> seropositivity. The selected level of statistical significance was <i>p</i> < 0.05. <i>Results</i>: A total of 1046 adults (mean age 47.2 years, SD = 11.5; 50% males) participated in the study. The overall age-standardized <i>H. pylori</i> seroprevalence was 63.1% (95% CI 60.4-66.7). Seropositivity increased with age, peaking at 80.3% in males aged 55-69. Higher seroprevalence was observed among those with basic education and those lacking access to municipal or heated water during childhood. Regression analysis revealed that male sex, aging, and lower education were significantly associated with <i>H. pylori</i> seropositivity. No significant link was found between <i>H. pylori</i> seroprevalence and gastrointestinal complaints. <i>Conclusions</i>: <i>H. pylori</i> seroprevalence remains high in Lithuanian adults, highlighting the need for ongoing surveillance and consideration of screening strategies. <i>H. pylori</i> infection was linked to sociodemographic and environmental factors but not dyspeptic complaints.