FALL IN THE PREVALENCE OF CHRONIC GASTRITIS OVER 15 YEARS - ANALYSIS OF OUTPATIENT SERIES IN FINLAND FROM 1977, 1985, AND 1992

To investigate whether the occurrence of chronic gastritis (and Helico bacter pylori acquisition) has changed in Finland in the past 15 years , the prevalence rates of chronic gastritis in biopsy specimens in con secutive series of outpatients (aged 20 or more) who had undergone dia gnostic upper gastrointestinal endoscopy in 1977 (702 patients), 1985 (1309 patients), or 1992 (1447 patients) were compared. The prevalence s of gastritis in these series were also compared with that in a rando m sample (438 subjects) of people who underwent endoscopy in 1974-76. It seemed that the prevalence rate of gastritis (and of prior H pylori acquisition) had fallen by 18% on average between 1977 and 1992, and that the prevalence of gastritis was significantly lower in the outpat ients in 1992 than in the random endoscopy sample in 1974-76. The redu ction was most noticeable in young age groups (20-49 years) in which t he decline was 38% (drop from 66% to 41%). In addition, it seemed that the prevalence of gastritis was very dissimilar in different birth co horts. The prevalence was high (70-80%) in 1977, 1985, and 1992 in the cohorts born at the beginning of the century and lower (40-50%) in th ose born during later decades. The prevalence rates had remained uncha nged in the same cohorts over the 15 years (from 1977 to 1992) suggest ing that the people had mainly been infected with H pylori and contrac ted gastritis before the age of 20. In conclusion, gastritis is a coho rt phenomenon and its prevalence has fallen in Finland in the last 15 years. This decrease is caused by a decline of the rate of H pylori ac quisition in birth cohorts, particularly in childhood and adolescence (below age of 20).