Objective Recent studies have suggested an association between Helicobacter pylori infection and iron deficiency. The aims were to investigate the prevalence and background factors of iron deficiency and H pylori infection in children.

Methods Consecutive outpatients aged 6–18 years, in whom a blood test was taken at the Unit of General Paediatrics, Children’s Clinic, in 2006–7, were asked to participate in the study. The child or the parent filled in a questionnaire on health problems, lifestyle and eating habits. Haemoglobin, mean corpuscular volume, serum ferritin, soluble transferrin receptors (s-TfR), C-reactive protein (CRP) and anti-H pylori IgG were measured. Children with increased CRP (>5 mg/l) were excluded.

Results Altogether 89% (n  =  288) of participating children were included in final analysis. The children were categorised into three groups by age: 6–12 years (n  =  105), 13–15 years (n  =  105) and 16–18 years (n  =  78). Iron deficiency (ferritin <12 μg/l) was found in 14% (n  =  42) of the children and 3% (n  =  9) had also anaemia (haemoglobin <115 g/l). The highest prevalence of iron deficiency, 22% (p<0.005) was found in children aged 16–18 years. The main background factor for developing iron deficiency in girls was the onset of menstruation (odds ratio 14; 95% CI 2 to 104). Altogether, 83 (29%) children were H pylori seropositive. We did not find any significant differences between the age groups or between the values of haemoglobin, mean corpuscular volume, ferritin or sTfR for children with or without H pylori seropositivity.

Conclusion Iron deficiency was commonest in children aged 16–18 years. Almost one third of all children were H pylori seropositive. H pylori seropositivity did not affect the development of iron deficiency.