The researchers investigated the incidence H. pylori infection in Swedish school children and reported their findings in the August issue of Gastroenterology.
They distinguished between risks of intrafamilial and extraneous child-to-child transmission among children with varying family backgrounds.
In the cross-sectional study, 695 of 858 (81%) 10-12-year-olds, in 36 school classes in Stockholm, donated blood and answered a questionnaire.
|Intrafamilial H. pylori transmission is very important.|
Infection was detected by enzyme-linked immunosorbent assay and confirmed by immunoblot and urea breath test.
The researchers found that, overall, 112 (16%) children were infected.
The seroprevalence was 2% among 435 children with Scandinavian parents and 55% among 144 children with origin in high prevalence areas (Middle East and Africa).
Odds ratios (ORs) were calculated and adjusted for gender, socioeconomic status, and family size.
Among children born in Scandinavia, the ORs for being seropositive were 39.1 and 5.6 when having parents born in high and medium prevalence areas, respectively, relative to children with Scandinavian parents.
Importantly, the prevalence of infection among the classmates was not found to be a risk factor for H. pylori infection.
Ylva Tindberg, of the Karolinska Institutet, Stockholm, concluded on behalf of the group, "Our data indicate that intrafamilial transmission is far more important than child-to-child transmission outside the family.
"The H. pylori prevalence in the parental generation may be a crucial determinant for the child's risk of contracting the infection."