Abstract
Helicobacter pylori (H. pylori) is considered to be a cause of gastric ulcer, gastric cancer and other diseases. The relationship between infection and the hygiene or housing circumstances of such patients in their childhood was explored. The study subjects were those who applied for a H. pylori antibody test, and were asked to fill out a questionnaire enclosed with a test kit, inquiring as to their hygiene and housing conditions when they were 10 years old. Of 5971 applicants, 5854 agreed to participate in the study. Associations between the six factors in the questionnaire and infection were calculated, and adjusted for sex, age and district. Drinking water, type of toilet, residential area, number of people in the house, and birth order showed significant correlations with H. pylori infection. The odds ratios (95% confidence intervals) were 0.73 (0.55-0.96) for tap water, 0.72 (0.63-0.84) for flush toilets, 0.74 (0.66-0.83) for urban location, 1.34 (1.09-1.64) for 7 or more people in the household, 1.19 (1.00-1.41) for 4th or 5th in birth order, and 1.47 (1.17-1.85) for 6th or more in birth order. No significant association with breast feeding was observed. These results suggest that infection with H. pylori may be associated with water-related sanitary factors in childhood, and that the bacillus may be transmitted within a family.