title: Decreased renal function in overweight and obese prepubertal children.
abstract: BACKGROUND
  Obesity is a potentially modifiable risk factor for the development and progression of kidney disease, both in adults and children. We aim to study the association of obesity and renal function in children, by comparing estimated glomerular filtration rate (eGFR) in nonoverweight and overweight/obese children. Secondarily, we aim to evaluate the accuracy of equations on eGFR estimation when compared to 24-h urinary creatinine clearance (CrCl).
  
  
  METHODS
  Cross-sectional study of 313 children aged 8-9 y, followed in the birth cohort Generation XXI (Portugal). Creatinine and cystatin C, GFR estimated by several formulas and CrCl were compared in 163 nonoverweight and 150 overweight/obese, according to World Health Organization growth reference.
  
  
  RESULTS
  Overweight/obese children had significantly lower eGFR, estimated by all methods, except for CrCl and revised Schwartz formula. Despite all children having renal function in the normal range, eGFR decreased significantly with BMI z-score (differences ranging from -4.3 to -1.1 ml/min/1.73 m(2) per standard deviation of BMI). The Zappitelli combined formula presented the closest performance to CrCl, with higher correlation coefficients and higher accuracy values.
  
  
  CONCLUSIONS
  Young prepubertal children with overweight/obesity already present significantly lower GFR estimations that likely represent some degree of renal impairment associated with the complex deleterious effects of adiposity.
authors.affiliation: 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: Liane
authors.initials: L
authors.lastname: Correia-Costa
authors.affiliation: 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: 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: EPIUnit - Institute of Public Health, University of Porto, Porto, Portugal.|Department of Clinical Pathology, Centro Hospitalar São João & Department of Biochemistry, Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: João Tiago
authors.identifier: http://orcid.org/0000-0003-4836-6311
authors.initials: JT
authors.lastname: Guimarães
authors.affiliation: Department of Nephrology, Centro Hospitalar São João, Porto, Portugal.
authors.forename: Manuela
authors.initials: M
authors.lastname: Bustorff
authors.affiliation: Division of Pediatric Nutrition, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Guerra
authors.affiliation: 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: Henrique
authors.initials: H
authors.lastname: Barros
authors.affiliation: 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: D050154:Adiposity; D000367:Age Factors; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015992:Body Mass Index; D016022:Case-Control Studies; D002648:Child; D003404:Creatinine / Q000097:blood / Q000652:urine; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007674:Kidney Diseases / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008954:Models, Biological; D063766:Pediatric Obesity / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D011174:Portugal; D011237:Predictive Value of Tests; D012307:Risk Factors
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D003404:Creatinine