High Prevalence of Helicobacter pylori Antibodies in an Institutionalized Population: Evidence for Person‐to‐Person Transmission

To evaluate the prevalence of H, pylori antibodies in mentally and physically handicapped adults living together in a long‐term care facility. One hundred twenty‐two institutionalized subjects from six living areas were compared to a normal representative Caucasian population obtained by random sampling from the urban population area of Melbourne. Serum samples from 1977 and 1989 from 122 subjects were tested for H. pylori antibody by an ELISA technique. The data were analyzed by Student's t test, χ² test and logistic regression. Ninety‐two of the 122 subjects (75%) from whom sera was collected in 1989 were seropositive for H. pylori, compared with only 23% in age‐ and sex‐matched control subjects (p < 0.0001). The prevalence of H. pylori antibodies in 1977 was 34% (42/122). Of the remaining 80 seronegative subjects, 51 (61.4%) converted to became positive in the 12‐yr interval. The annual seroconversion rate was 7.4%, with an average of 4.25 newly positive subjects each year. The prevalence of H. pylori in 1989 was significantly higher than in 1977 after adjustment for age (odds ratio 2.39, 95% CI 1.1–5.3, p= 0.03). H. pylori antibodies are significantly more prevalent in institutionalized adults compared with controls from the general population. These data support the hypothesis that H. pylori is acquired by either fecal‐oral or oral‐oral transmission.