As shown in Table 1, information on H. pylori+ and H. pylori− patients was collected using a questionnaire on the factors affecting H. pylori infection, including sex, age, occupation, residential area, body type, marital status, education level, family size, annual income, cigarette smoking, alcohol consumption, history of periodontal disease, hygiene of dining place, main source of drinking water, drinking unheated water, and vitamin D serum level. The gene discussed is FUT1; the disease is periodontal disorder.