HSPD1 and gastroesophageal reflux disease: Using five different methods to analyze the antibody levels of Helicobacter pylori IgG, CagA, VacA, UREA, hydrogen peroxide enzyme, OMP, and GroEL, under the IVW method, an increased risk of GERD was associated with Helicobacter pylori IgG antibody levels (odds ratio [OR] = 1.003, 95% CI 1.00–1.004, P = 0.043) (See Fig 2).