Pediatr Res. 2015 Jul 7. doi: 10.1038/pr.2015.130. [Epub ahead of print]

Decreased renal function in overweight and obese prepubertal children.

Correia-Costa L1, Caldas Afonso A1, Schaefer F2, Guimarães JT3, Bustorff M4, Guerra A5, Barros H6, Azevedo A6.

Author information

• 11] EPIUnit -Institute of Public Health, University of Porto, Porto, Portugal [2] Division of Pediatric Nephrology, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.
• 2Division of Pediatric Nephrology, Center for Pediatrics and Adolescent Medicine, University of Heidelberg, Heidelberg, Germany.
• 31] EPIUnit -Institute of Public Health, University of Porto, Porto, Portugal [2] Department of Clinical Pathology, Centro Hospitalar São João & Department of Biochemistry, Faculty of Medicine, University of Porto, Porto, Portugal.
• 4Department of Nephrology, Centro Hospitalar São João, Porto, Portugal.
• 5Division of Pediatric Nutrition, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.
• 61] EPIUnit -Institute of Public Health, University of Porto, Porto, Portugal [2] Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine of University of Porto, Porto, Portugal.

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-hour urinary creatinine clearance (CrCl).

METHODS:

Cross-sectional study of 313 children aged 8-9 years, 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 WHO 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/1.73m2 per standard deviation of BMI). The Zappitelli combined formula presented the closest performance to CrCl, with higher correlation coefficients and higher accuracy values.

CONCLUSION:

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.