title: Sodium intake and blood pressure in children and adolescents: protocol for a systematic review and meta-analysis.
abstract: BACKGROUND
  Hypertension is a major risk factor for cardiovascular diseases. In adults, high sodium intake is associated with elevated blood pressure. In children, experimental studies have shown that reducing sodium intake can reduce blood pressure. However, their external validity is limited, notably because the sodium reduction was substantial and not applicable in a real-life setting. Observational studies, on the other hand, allow assess the association between blood pressure and sodium intake across usual levels of consumption. There is also evidence that the association differs between subgroups of children according to age and body weight. Our objective is to conduct a systematic review and meta-analysis of experimental and observational studies on the association between sodium intake and blood pressure in children and adolescents and to assess whether the association differs according to age and body weight.
  
  
  METHODS
  A systematic search of the MEDLINE, EMBASE, CINAHL and CENTRAL databases will be conducted and supplemented by a manual search of bibliographies and unpublished studies. Experimental and observational studies involving children or adolescents between 0 and 18 years of age will be included. The exposure will be dietary sodium intake, estimated using different methods including urinary sodium excretion. The outcomes will be systolic and diastolic blood pressure, elevated blood pressure and hypertension. If appropriate, meta-analyses will be performed by pooling data across all studies together and separately for experimental and observational studies. Subgroup meta-analyses by age and body weight will be also conducted. Moreover, separate meta-analyses for different sodium intake levels will be conducted to investigate the dose-response relationship.
  
  
  BACKGROUND
  This systematic review and meta-analysis will be published in a peer-reviewed journal. A report will be prepared for national authorities and other stakeholders in the domains of nutrition, public health, and child health in Switzerland.
  
  
  BACKGROUND
  CRD42016038245.
authors.affiliation: Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital (CHUV), Lausanne, Switzerland.
authors.forename: Magali
authors.initials: M
authors.lastname: Leyvraz
authors.affiliation: Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital (CHUV), Lausanne, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Taffé
authors.affiliation: Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital (CHUV), Lausanne, Switzerland.
authors.forename: Angeline
authors.initials: A
authors.lastname: Chatelan
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, Canada.
authors.forename: Gilles
authors.initials: G
authors.lastname: Paradis
authors.affiliation: Department of Pediatrics, Hospital of Valais, Sion, Switzerland Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: René
authors.initials: R
authors.lastname: Tabin
authors.affiliation: Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital (CHUV), Lausanne, Switzerland.
authors.forename: Pascal
authors.initials: P
authors.lastname: Bovet
authors.affiliation: Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital (CHUV), Lausanne, Switzerland.
authors.forename: Murielle
authors.initials: M
authors.lastname: Bochud
authors.affiliation: Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital (CHUV), Lausanne, Switzerland Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, Canada.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Chiolero
keywords: EPIDEMIOLOGY; NUTRITION & DIETETICS