title: Do gastrointestinal tract infections in infancy increase blood pressure in childhood? A cohort study.
abstract: BACKGROUND
  It has been hypothesised that dehydration in infancy could permanently increase sodium retention, raising blood pressure in later life. In this study, the association between gastrointestinal tract infection in infancy, a clinically relevant exposure often accompanied by dehydration, and raised blood pressure in childhood was investigated.
  
  
  METHODS
  Data from a cohort study nested within a cluster-randomised trial of breastfeeding promotion in the Republic of Belarus were analysed. 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) and hospitalisations 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 hospitalisation 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 mm Hg; 95% CI -0.52 to 0.43) or hospitalisation for gastrointestinal infection (difference=-0.22 mm Hg; -1.07 to 0.64) in infancy. Nor were associations observed between diastolic blood pressure and any gastrointestinal infection during infancy or hospitalisation for gastrointestinal infection during infancy or childhood.
  
  
  CONCLUSIONS
  No evidence was found to prove that hospitalisation for gastrointestinal infection in infancy or childhood leads to raised blood pressure at age 6.5 years in a developed country setting.
authors.affiliation: Department of Social Medicine, University of Bristol, 39 Whatley Road, Bristol BS8 2PS, UK. richard.martin@bristol.ac.uk
authors.forename: R M
authors.initials: RM
authors.lastname: Martin
authors.forename: M S
authors.initials: MS
authors.lastname: Kramer
authors.forename: M
authors.initials: M
authors.lastname: Dahhou
authors.forename: R W
authors.initials: RW
authors.lastname: Platt
authors.forename: R
authors.initials: R
authors.lastname: Patel
authors.forename: N
authors.initials: N
authors.lastname: Bogdanovich
authors.forename: L
authors.initials: L
authors.lastname: Matush
authors.forename: G
authors.initials: G
authors.lastname: Davey Smith
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D001942:Breast Feeding; D002648:Child; D002675:Child, Preschool; D054869:Clinical Audit; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005767:Gastrointestinal Diseases / Q000150:complications* / Q000453:epidemiology; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D007223:Infant; D008297:Male; D015995:Prevalence; D002094:Republic of Belarus; D012959:Socioeconomic Factors