Do gastrointestinal tract infections in infancy increase blood pressure in childhood? Cohort study

Background: It has been hypothesized that dehydration in infancy could permanently increase sodium retention, raising blood pressure in later life. We investigated whether gastrointestinal tract infection in infancy, a clinically relevant exposure often accompanied by dehydration, is associated with raised blood pressure in childhood. Methods: We analysed data from a cohort study nested within a cluster-randomized trial of breastfeeding promotion in the Republic of Belarus. 17,046 healthy breastfed infants were enrolled from 31 maternity hospitals. 13,889 (81.5%) children were followed-up at 6.5 years. Exposure measures were: any gastrointestinal infection in infancy (to 1 year); hospitalizations for gastrointestinal infection in infancy and in childhood (1-6.5 years). The outcomes were systolic and diastolic blood pressure at age 6.5 years. Results: The prevalence of any gastrointestinal infection in infancy, and of hospitalization for gastrointestinal infection in infancy or childhood, was 11.4%, 3.2% and 6.0%, respectively. No associations were observed between systolic blood pressure and any gastrointestinal infection (mean difference in those with minus those without infection = -0.04 mmHg; 95% CI: -0.52, 0.43) or hospitalization for gastrointestinal infection (difference = -0.22 mmHg; -1.07, 0.64) in infancy. Nor were associations observed between diastolic blood pressure and any gastrointestinal infection during infancy or hospitalization for gastrointestinal infection during infancy or childhood. Conclusion: We found no evidence that hospitalization for gastrointestinal infection in infancy or childhood leads to raised blood pressure at age 6.5 years in a developed country setting.