The excess prevalence of cognitive impairment, according to infection with CagA positive strains of H. pylori, decreased from an unadjusted prevalence ratio of 2.6 (95% CI: 1.7, 4.1) to a multivariate (age and education) adjusted prevalence ratio of 1.5 (95% CI: 1.0, 2.2), that is by 42%, and such excess prevalence was borderline significant at 5% level (adjusted Satterthwaite-adjusted Chi-square p-value = 0.12) (Panel A of Figure 2). This evidence concerns the gene S100A8 and infection.