Beschreibung:
<jats:p><i>Background:</i> An increase in the prevalence of allergic conditions has been documented in Finland, correlating with the diminishing prevalence of <i>Helicobacter pylori</i> infections. We investigated whether the increase of allergic sensitisation still continues and correlates with the prevalence of <i>H. pylori</i> infections. <i>Methods:</i> The sera from 958 pregnant women in 1983, 1989, 1995 and 2001 were analysed for the presence of antibodies against <i>H. pylori</i>. In addition, allergen-specific IgE antibodies and total levels of IgE antibodies were measured. <i>Results:</i> A clear birth cohort effect was found in the prevalence of allergic sensitization: allergen-specific IgE was more frequent among recent birth cohorts than earlier ones (p = 0.001). The frequency of <i>H. pylori</i> antibodies followed the opposite trend (p < 0.001) and the increase in allergic sensitisation was only seen among <i>H. pylori</i>-negative women. A modest increase was also seen in allergic sensitisation between the 4 time series among the <i>H. pylori</i>-negative subjects (p = 0.04). Total IgE levels did not differ between birth cohorts or time series. <i>Conclusion:</i> The results suggest that hygiene-related environmental factors have played a role in the increase of allergic sensitisation during the last decades.</jats:p>