COUNTRY-SPECIFIC CONSTANCY BY AGE IN CAGA(-PYLORI INFECTIONS() PROPORTION OF HELICOBACTER)

Helicobacter pylori strains may be either cagA(+) or cagA(-), and in l ogitudinal studies, infection with a cagA(+) strain has been associate d with increased risk for the development of atrophic gastritis and ca ncer of the distal stomach. We sought to determine the relative propor tion of strains producing CagA in different geographic locales, and th e extent to which CagA seroprevalence varied in countries with differe nt gastric and esophageal cancer rates. Using an enzyme-linked immunos orbent assay (ELISA) to detect serum IgG to CagA, we examined sera fro m 468 asymptomatic H. pylori-infected adults from Canada, Peru, China, Thailand, The Netherlands and 3 different ethnic groups in New Zealan d. The CagA seroprevalence in Peru and Thailand (82.2% and 78.8%, resp ectively) were each substantially higher than for the Chinese (37.9%), Canadian (41.9%), Dutch (39.0%) and New Zealand (28.2%) subjects, but within each population, rates were relatively constant across gender and age groups. Reported gastric but not esophageal cancer rates for t he 8 studied populations were significantly associated with H. pylori seroprevalence. Variation in CagA positivity rates was not significant ly associated with variation in either gastric or esophageal cancer ra tes. Our data suggest that CagA seroprevalence is not the major factor influencing gastric cancer rates. (C) 1997 Wiley-Liss, Inc.