This joint effect is reflected in the adjusted probabilities for iron deficiency: Individuals with H. pylori infection and higher levels of hepcidin had a probability of 0.24 (CI 95% 0.14–0.34) for iron deficiency, and this probability was 0.24 (CI 95% 0.14–0.33) in children without H. pylori infection and lower levels of hepcidin. This evidence concerns the gene HAMP and Iron deficiency anemia.