Objective: Helicobacter pylori infection is commonly associated with low-income settings and inadequate sanitation. Iron deficiency anemia, although a rare condition, has been linked to the widespread infection of H. pylori. This study aims to report the seroprevalence of H. pylori among Costa Rican preschool children enrolled in two national nutritional programs: the Education and Nutrition Centers (CEN) and the Children’s Centers for Nutrition and Comprehensive Care (CINAI). Furthermore, we will investigate the correlation between H. pylori seropositivity and various hematological parameters, as well as specific socioeconomic and environmental factors within this cohort.

Materials and Methods: Based on a previous study, a subsample of 428 children, aged between 1 and 7 years, was selected from 13 Education and Nutrition Centers (CEN-CINAI) located in the Central Southern Region of Costa Rica. Socioeconomic data and baseline laboratory values – including iron indices, hemoglobin, hematocrit, and vitamin D levels – were sourced from the original study by Solano-Barquero et al (2018). In the present study, serum samples were analyzed for IgG antibodies against H. pylori using an ELISA.

Results: The overall seroprevalence of H. pylori infection was estimated at 15.0%. The infection was more frequent among children without proper sewage or septic tank systems (OR: 3.2, 95% CI: 1.3-8.2) and those living in households with inadequate floor material (OR: 4.0, 95% CI: 1.1-14.7). Co-protozoal infections also represented an additional risk factor (OR: 3.2, 95% CI: 1.5-7.5). Conversely, recent antiparasitic treatment was found to be a protective factor (OR: 0.3, 95% CI: 0.1-0.7). Anemia prevalence was lower in the subsample (4.5%) than in the original study (7.5%) and had no correlation with H. pylori infection. Serum iron levels, ferritin, TIBC, and vitamin D had no significant differences between infected and non-infected children.

Conclusions: In this cohort, no correlation was found between H. pylori infection and iron deficiency anemia. However, the observed seroprevalence of 15.0% is consistent with rates reported for children under 10 years of age in other Latin American countries. The findings suggest that environmental factors, such as sewage disposal and housing materials, along with co-infections and antiparasitic treatment, play a significant role in the epidemiology of H. pylori infection in this population.