Time trends and geographical variation of Helicobacter pylori antibodies in Finland were investigated by enzyme immunoassay in 20- to 34-year-old randomly selected females from six localities during 1969–73 (n = 375), and 15- to 45-year-old females representing nine communities and four geographical areas in 1983 (n = 882) and 1995 (n = 842). In the six communities investigated at three different time points, the overall prevalence declined from 38 to 12%, with an emphasis on the latter 12 years. The regionally varying rate of decrease in helicobacter prevalence changed the pre-existing geographical variation, leaving northern Finland with the highest rate. A 10%-units higher local helicobacter prevalence seemed to predict a 23% (95% CI 3–44%) higher gastric cancer incidence 20 years later. The overall decline in helicobacter seropositivity is consistent with earlier reports from Finland and other developed countries, and supports the cohort theory as an explanation for the age-related increase in H. pylori seroprevalence.

Specific colostral antibodies were useful in the prevention of Helicobacter infection in a mouse model. The results of the treatment trials were controversial but a similar colostral immune preparation against H. pylori could be effective and useful in preventing infections in humans and during antibiotic treatment.

The prevalence of H. pylori antibodies in Finnish children studied was low. Although the majority of new infections were found in children younger than 7 years of age, new Helicobacter infections were acquired throughout childhood and adolescence. Once acquired H. pylori infection, as verified by Helicobacter antibodies, persisted.

The potential preventability of serious helicobacter-associated diseases - especially gastric cancer - has evoked interest in eradicating this pathogen from the population. We assessed the efficacy of the pioneering screen and treat intervention project in Vammala by studying helicobacter seroprevalence in pregnant women representing the normal population. Consecutive maternity clinic samples from native Finnish females at five different localities in 1995 (n=701) and 2000 (n=772) were investigated for class IgG H. pylori antibodies by enzyme immunoassay (Pyloriset EIA-G III, Orion Diagnostica, Espoo, Finland). In Vammala the change in helicobacter seroprevalence was -13%-units (between 1995 and 2000; p=0.0125, chi-square test) in > or =29-year-old females, +1.6%-units (difference statistically non-significant) in <29-year-old females, and -5.5%-units (difference statistically non-significant) in the whole study population. In the four reference localities studied, all the corresponding changes remained statistically non-significant. Thus, in Vammala the programme applied accelerated the decline of helicobacter infections in 29- to 45-year-old females and in 2000 the seroprevalence rate had also become significantly lower than that of the four reference communities combined (7.6% versus 13.5%, respectively, p=0.0433, chi-square test). The final outcome of the intervention project, i.e. the long-term effect of this decline on gastric cancer and peptic ulcer disease, remains to be evaluated.

The age-related increase in H. pylori seroprevalence did not continue in the oldest age group alive in Finland. This may be explained partly by a relatively high frequency of atrophic gastritis (as suggested by low PG I values) in H. pylori-negative centenarians, but other factors--such as selective H. pylori-related mortality--may also have contributed to the fairly low seroprevalence (66%) observed.