Association between Helicobacter pylori antibody-positive status and extragastric diseases in Japanese junior high school students

Background: Helicobacter pylori (H. pylori) infection causes various extragastric diseases. Its transmission route has still not been clarified. However, no large-scale studies have examined the extragastric diseases caused by H. pylori in adolescents. This study aimed to examine the association of H. pylori infection with anemia, serum cholesterol levels, physique, and birth delivery method (vaginal or cesarean) in a large number of Japanese adolescents. Methods: From 2016 to 2018, we screened 2,399 adolescents (aged 13–15 years) in their second and third years of junior high school using an enzyme-linked immunosorbent assay-based antibody test. Red blood cells, hemoglobin, hematocrit, total cholesterol, high-density lipoprotein (HDL) cholesterol, and serum antibody levels were measured. Results: Hemoglobin and hematocrit levels were significantly lower in the H. pylori antibody-positive group than in the H. pylori antibody-negative group in both sexes (boys: P = 0.0004 and 0.0022; girls: P = 0.0019 and 0.0005, respectively). Total cholesterol and non-HDL cholesterol levels were significantly higher in the H. pylori-positive group than in the H. pylori-negative group among boys (P = 0.0370 and 0.0293 respectively). There was no significant difference in body mass index percentile and birth delivery method between the H. pylori-positive and H. pylori-negative groups in both boys and girls. Conclusions: Among Japanese junior high school students, H. pylori antibody-positive status was associated with anemia in both sexes while total cholesterol and non-HDL cholesterol levels were associated among boys. There was no association between H. pylori antibody status, body mass index percentile, and birth-delivery method.