Seroprevalence of immunoglobulin G, M, and A antibodies to Helicobacter pylori in an unselected Danish population.

The seroprevalences of increased levels of immunoglobulin G (lgG), M (lgM), and A (lgA) antibodies to Helicobacter pylori were assessed by enzyme-linked immunosorbent assay techniques in 3,589 Danes who participated in a population study in Copenhagen County in 1982. A total of 33.9% of the study population had one or more classes of increased antibodies to H. pylori. Increased levels of lgG, lgM, and lgA antibodies to H. pylori were seen in 25.9% (95% confidence interval (Cl) 24.5-27.3), 4.5% (95% Cl 2.2-7.0), and 12.0% (95% Cl 10.9-13.1) of the participants, respectively. Women were significantly more likely than men to be seropositive for lgM antibodies (Mantel-Haenszel summary odds ratio = 1.85, 95% Cl 1.34-2.57). Seropositivity for lgM antibodies to H. pylori was found less often with increasing age. An lgG antibody response was not seen in 23.7% of cases with overall increased antibodies to H. pylori. Increased levels of lgG or lgA antibodies were more frequent in people with a history of peptic ulcer disease. Seroprevalences of increased H. pylori antibodies are high in unselected populations. Primary H. pylori infections are contracted at all ages, but infection rates decline with age. Inclusion of measurements of lgA and lgM antibody levels in future screening for H. pylori may improve the diagnostic sensitivity of serologic analyses.