title: Low sodium status in cystic fibrosis-as assessed by calculating fractional Na(+) excretion-is associated with decreased growth parameters.
abstract: In CF infants, normonatremic Na(+) depletion (NNaD), identified by fractional Na(+) excretion (FENa) values <0.5%, was recently linked to impaired growth. Our paper investigates the relationship between FENa and growth in CF children >2years.
  
  
  
  FENa values were calculated in 35 CF and 24 control children, and tested for correlations with z-scores for weight, height and BMI.
  
  
  
  All CF children and controls had normal plasma Na(+) concentrations. A total of 25 of 35 (71.4%) CF patients had decreased FENa values <0.5% (group I). FENa results of 10 CF patients (group II) and 23/24 controls (group III) were normal. In Na(+)-depleted CF children, compared to normal controls, mean z-scores for weight (-0.18±0.87 vs +1.03±0.57, p<0.001), height (-0.06±0.89 vs +0.53±0.72, p=0.009) and BMI (-0.22±0.87 vs +1.00±1.06, p<0.001) were significantly reduced. Also, we found positive correlations between FENa values and z-scores for weight (r=0.521), height (r=0.292) and BMI (r=0.468), respectively.
  
  
  
  NNaD may contribute to poor growth in CF.
authors.affiliation: Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Christiane
authors.initials: C
authors.lastname: Knepper
authors.affiliation: Department of Pediatrics III, Cystic Fibrosis Center, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Helmut
authors.initials: H
authors.lastname: Ellemunter
authors.affiliation: Department of Pediatrics III, Cystic Fibrosis Center, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Eder
authors.affiliation: Department of Pediatrics III, Cystic Fibrosis Center, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Katharina
authors.initials: K
authors.lastname: Niedermayr
authors.affiliation: Department of General and Transplant Surgery, Division of Pediatric Surgery, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Bettina
authors.initials: B
authors.lastname: Haerter
authors.affiliation: Division of Medical Statistics and Informatics, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Philipp
authors.initials: P
authors.lastname: Hofer
authors.affiliation: Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Sabine
authors.initials: S
authors.lastname: Scholl-Bürgi
authors.affiliation: Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Müller
authors.affiliation: Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria. Electronic address: peter.heinz-erian@tirol-kliniken.at.
authors.forename: Peter
authors.initials: P
authors.lastname: Heinz-Erian
mesh_terms: D001317:Austria / Q000453:epidemiology; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D066238:Cutaneous Elimination; D003550:Cystic Fibrosis / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D003967:Diarrhea / Q000150:complications / Q000503:physiopathology; D005260:Female; D006130:Growth Disorders / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D007010:Hyponatremia / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D066237:Intestinal Elimination; D008297:Male; D011446:Prospective Studies; D012964:Sodium / Q000097:blood / Q000378:metabolism; D013223:Statistics as Topic; D013546:Sweating
chemical_list: D012964:Sodium
keywords: Cystic fibrosis; Fractional sodium excretion; Growth retardation; Normonatremic sodium depletion