title: Elevated salt and nitrate levels in drinking water cause an increase of blood pressure in schoolchildren.
abstract: OBJECTIVE
  To assess the influence on blood pressure in schoolchildren, of elevated sodium (Na(+)) and nitrate (NO(-)(3)) levels in the drinking water.
  
  
  METHODS
  The blood pressure was recorded in three groups of age- and weight-matched schoolchildren (fourth and fifth graders) ingesting differing Na(+) and NO(-)(3) concentrations with their drinking water. Group 1 (n = 452) imbibed high-Na(+), high-NO(-)(3) water (196 and 49 mg/l, respectively); group 2 (n = 418) consumed low-Na(+), high-NO(-)(3) water (25 and 49 mg/l, respectively) and group 3 (n = 86) drank low-Na(+), low-NO(-)(3) water (35 and 25 mg/l, respectively). The chloride (Cl(-)) concentrations varied in parallel to those of Na(+).
  
  
  RESULTS
  Systolic blood pressure (SBP) and mean arterial pressure (MAP) were significantly increased in group 1 versus groups 2 and 3 (115.6 +/- 12.2 and 86.4 +/- 9.6 mm Hg vs. 111.1 +/- 11.6 and 83 +/- 8.3 and 107 +/- 8.8 and 81 +/- 7.2 mm Hg, respectively, p < 0.05). The SBP in group 2 was also significantly higher than in group 3 (111.1 +/- 11.6 vs. 107 +/- 8.8 mm Hg; p < 0.05).
  
  
  CONCLUSIONS
  Elevated Na(+) (and possibly Cl(-)) in combination with high NO(-)(3) concentrations in drinking water leads to an increase of SBP and MAP in fourth and fifth graders. The effects of Na(+) (and/or Cl(-)) and NO(-)(3) on SBP and MAP appear to be additive, yet independent of each other.
authors.affiliation: Pediatric Nephrology Clinic, Meir Hospital, Kfar Saba, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Pomeranz
authors.forename: Z
authors.initials: Z
authors.lastname: Korzets
authors.forename: D
authors.initials: D
authors.lastname: Vanunu
authors.forename: H
authors.initials: H
authors.lastname: Krystal
authors.forename: B
authors.initials: B
authors.lastname: Wolach
mesh_terms: D001794:Blood Pressure / Q000187:drug effects*; D002648:Child; D003404:Creatinine / Q000097:blood; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D009566:Nitrates / Q000008:administration & dosage / Q000494:pharmacology*; D012964:Sodium / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D014881:Water Supply
chemical_list: D009566:Nitrates; D012964:Sodium; D003404:Creatinine