title: Gender and obesity modify the impact of salt intake on blood pressure in children.
abstract: BACKGROUND
  Most modifiable risk factors for high blood pressure (BP), such as obesity and salt intake, are imprinted in childhood and persist into adulthood. The aim of our study was to evaluate the intake of salt in children and to assess its impact on BP taking into account gender and nutritional status.
  
  
  METHODS
  A total of 298 children aged 8-9 years were evaluated in a cross-sectional study. Anthropometric measurements and 24-h ambulatory monitoring were performed, and salt intake was determined by 24-h urinary sodium excretion.
  
  
  RESULTS
  The average estimated salt intake among the entire cohort of children enrolled in the study was 6.5 ± 2.2 g/day, and it was significantly higher in boys than in girls (6.8 ± 2.4 vs. 6.1 ± 1.9 g/day, respectively; p = 0.018) and in overweight/obese children than in normal weight children (6.8 ± 2.4 vs. 6.1 ± 2.0 g/day, respectively; p = 0.006). Salt intake exceeded the upper limit of the US Dietary Reference Intake in 72% of children. Daytime systolic BP increased by 1.00 mmHg (95% confidence interval 0.40-1.59) per gram of daily salt intake in overweight/obese boys, but not in normal weight boys or in girls.
  
  
  CONCLUSIONS
  Our results demonstrate an extremely high salt intake among 8- to 9-year-old Portuguese children. Higher salt intake was associated with higher systolic BP in boys, specifically in those who were overweight/obese. Longitudinal studies are needed to further evaluate the causal relationship between obesity and high BP and the mechanism by which salt intake modulates this relationship. Nonetheless, based on our results, we urge that dietary salt reduction interventions, along with measures to fight the global epidemic of obesity, be implemented as early in life as possible.
authors.affiliation: Epidemiology Research Unit (EPIUnit), Institute of Public Health, University of Porto, Porto, Portugal. liane@med.up.pt.|Division of Pediatric Nephrology, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal. liane@med.up.pt.|Instituto de Saúde Pública da Universidade do Porto (ISPUP), Rua das Taipas n° 135, 4050-600, Porto, Portugal. liane@med.up.pt.
authors.forename: Liane
authors.initials: L
authors.lastname: Correia-Costa
authors.affiliation: Epidemiology Research Unit (EPIUnit), Institute of Public Health, University of Porto, Porto, Portugal.|Department of Pharmacology and Therapeutics, Faculty of Medicine of University of Porto, Porto, Portugal.
authors.forename: Dina
authors.initials: D
authors.lastname: Cosme
authors.affiliation: Department of Internal Medicine, Centro Hospitalar São João, Porto, Portugal.|Center for Research in Health Technologies and Information Systems (CINTESIS), Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Nogueira-Silva
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Medicine of University of Porto, Porto, Portugal.|Center for Drug Discovery and Innovative Medicines (MedInUP), University of Porto, Porto, Portugal.|Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy of Porto, University of Porto, Porto, Portugal.
authors.forename: Manuela
authors.initials: M
authors.lastname: Morato
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Medicine of University of Porto, Porto, Portugal.|Center for Drug Discovery and Innovative Medicines (MedInUP), University of Porto, Porto, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Sousa
authors.affiliation: Division of Pediatric Cardiology, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Moura
authors.affiliation: Division of Pediatric Cardiology, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Mota
authors.affiliation: Center for Research in Health Technologies and Information Systems (CINTESIS), Faculty of Medicine, University of Porto, Porto, Portugal.|Division of Pediatric Nutrition, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Guerra
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Medicine of University of Porto, Porto, Portugal.|Center for Drug Discovery and Innovative Medicines (MedInUP), University of Porto, Porto, Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Albino-Teixeira
authors.affiliation: Division of Pediatric Cardiology, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Areias
authors.affiliation: Division of Pediatric Nephrology, Center for Pediatrics and Adolescent Medicine, University of Heidelberg, Heidelberg, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Schaefer
authors.affiliation: Epidemiology Research Unit (EPIUnit), Institute of Public Health, University of Porto, Porto, Portugal.|Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine of University of Porto, Porto, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Lopes
authors.affiliation: Epidemiology Research Unit (EPIUnit), Institute of Public Health, University of Porto, Porto, Portugal.|Division of Pediatric Nephrology, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.
authors.forename: Alberto Caldas
authors.initials: AC
authors.lastname: Afonso
authors.affiliation: Epidemiology Research Unit (EPIUnit), Institute of Public Health, University of Porto, Porto, Portugal.|Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine of University of Porto, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Azevedo
mesh_terms: D001794:Blood Pressure; D001795:Blood Pressure Determination; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D050177:Overweight / Q000150:complications*; D063766:Pediatric Obesity / Q000150:complications*; D012307:Risk Factors; D012737:Sex Factors; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage*
chemical_list: D017673:Sodium Chloride, Dietary
keywords: Blood pressure; Children; Gender; Hypertension; Obesity; Salt intake