Helicobacter pylori infection among children in Riga, Latvia

Abstract

Aims: To identify the prevalence of H.pylori among asymptomatic children and their parents in Riga, Latvia. To study the age of acquisition for H.pylori and the risk factors and symptoms associated with H.pylori infection. To identify the prevalence of H.pylori and infection with cagA-positive and cagA-negative strains among dyspeptic children.

Materials and methods: H.pylori infection was detected by 13C-urea breath test (UBT) in 142 consecutive asymptomatic children (aged 112 years) and parents of 40 children and by monoclonal stool antigen test in 146 asymptomatic children (aged 0.5-5 years). The parents were asked to fill out a standardised questionnaire about possible risk factors. In 130 consecutive children (aged 8-18 years) with upper gastrointestinal symptoms coming for upper gastrointestinal endoscopy H.pylori infection was detected by rapid urease test and/or culture. Endoscopic changes were evaluated. In 56 consecutive H.pylori positive patients presence of cagA and vacA was detected by PCR. In culture positive patients (n=31) H.pylori-DNA was extracted from 10 different colonies of primary cultures and from a mixture of colonies and tested for the presence of cagA. Anti- CagA and VacA antibodies were assessed by immunoblot. The prevalence of H.pylori was compared between 55 consecutive asymptomatic children and 40 consecutive symptomatic children with symptoms from upper gastrointestinal tract of the same age. Statistical analysis: 72 or Ficher's test, and logistic regression analysis.

Results: The overall prevalence of H.pylori infection among asymptomatic children by UBT was 19%; by stool antigen test - 18 %. The age of the youngest H.pylori positive children was 4 and 6 months. The presence of infection was independently inversely related to previous antibiotic treatment (p=0.01) and higher educational status of a mother (p=0.04) and significantly associated with parental H.pylori status (p-0.003). Among symptomatic children the prevalence of infection was 54%(70/130) and it was significantly higher among patients with reflux oesophagitis (OR = 5.5, p=0.03) and a duodenal ulcer or erosions in duodenum or oesophagus (OR =5.5; p=0.01) compared to patients with hyperemic gastropathy alone. Previous or current infection with cagA-positive strains was observed in 50/56 patients. The presence of both cagA-positive and cagA-negative genotypes in the same individual was identified in 11 of the 31 culture-positive patients. In logistic regression analysis no significant difference between the prevalence of H.pylori in asymptomatic and symptomatic children could be shown.

Conclusions: The prevalence of H.pylori infection among asymptomatic children in Riga is higher than in Western countries, but it is similar to the prevalence rate in some Eastern European countries. H.pylori infection is present already during the first year of life. Infection with H.pylori is independently inversely related to previous antibiotic treatment and is significantly associated with parental H.pylori status and educational status of mother. Among symptomatic children H.pylori prevalence was significantly higher among patients with reflux oesophagitis and patients with an ulcer or erosions were more likely to have H.pylori infection. Both cagA+ and cagA- strains could be identified in a large proportion of samples from dyspeptic children and previous or current infection with cagA' strains was observed in 89% of patients. The prevalence of H.pylori infection was not higher among children with gastrointestinal symptoms compared to the prevalence among asymptomatic children of the same age.