The Effects of Exercise on Abdominal Fat and Liver Enzymes in Pediatric Obesity: A Systematic Review and Meta-Analysis.
BACKGROUND
Despite the prevalence of obesity and the multiple position stands promoting exercise for the treatment of obesity and hepatic function, a meta-analytic approach has not previously been used to examine the effects in the pediatric population. The aim of the study was to determine the effectiveness of exercise interventions on abdominal fat, liver enzymes, and intrahepatic fat in overweight and obese youth.


METHODS
A computerized search was made using three databases. The analysis was restricted to studies that examined the effect of supervised exercise interventions on abdominal fat (visceral and subcutaneous fat), liver enzymes (alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase), and intrahepatic fat. Fourteen clinical trials (1231 youths) were eligible for inclusion in this systematic review and meta-analysis. Standardized mean difference [SMD] and 95% confidence intervals (CIs) were calculated.


RESULTS
Exercise was associated with a significant reduction in visceral (SMD = -0.661; 95% CI, -0.976 to -0.346; p < 0.001), subcutaneous (SMD = -0.352; 95% CI, -0.517 to -0.186; p < 0.001) and intrahepatic fat (SMD = -0.802; 95% CI, -1.124 to -0.480; p < 0.001), as well as gamma-glutamyl transferase (SMD = -0.726; 95% CI, -1.203 to -0.249; p < 0.001), but did not alter any other liver enzyme. Subgroup analysis recommends exercise programs that involve aerobic exercise longer than three sessions per week.


CONCLUSIONS
This meta-analysis supports current recommendation for physical exercise, mainly aerobic, as an effective intervention for nonalcoholic fatty liver disease progression by targeting hepatic lipid composition, visceral and subcutaneous adipose tissue. Systematic review registration: PROSPERO CRD42016042163.
1 Centro de Estudios para la Medición de la Actividad Física (CEMA), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario , Bogotá DC, Colombia .|2 Grupo de Investigación en Ejercicio Físico y Deporte, Vicerrectoría de investigación, Universidad Manuela Beltrán , Bogotá, DC, Colombia .
Katherine
K
González-Ruiz
1 Centro de Estudios para la Medición de la Actividad Física (CEMA), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario , Bogotá DC, Colombia .
Robinson
R
Ramírez-Vélez
1 Centro de Estudios para la Medición de la Actividad Física (CEMA), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario , Bogotá DC, Colombia .
Jorge Enrique
JE
Correa-Bautista
3 Department of Physical Medicine and Rehabilitation, University of Michigan , Ann Arbor, MI.|4 Global REACH, University of Michigan Medical School, University of Michigan , Ann Arbor, MI.
Mark D
MD
Peterson
5 Laboratorio de Ciencias de la Actividad Física, el Deporte y la Salud, Facultad de Ciencias Médicas, Universidad de Santiago de Chile (USACH) , Santiago, Chile .
Antonio
A
García-Hermoso
D050153:Abdominal Fat / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000293:Adolescent; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D002648:Child; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008099:Liver / Q000201:enzymology*; D016239:MEDLINE; D008297:Male; D065626:Non-alcoholic Fatty Liver Disease / Q000517:prevention & control / Q000628:therapy; D063766:Pediatric Obesity / Q000503:physiopathology / Q000628:therapy*; D050151:Subcutaneous Fat / Q000503:physiopathology; D005723:gamma-Glutamyltransferase / Q000097:blood
D005723:gamma-Glutamyltransferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase
ectopic adiposity; fatty liver; nonalcoholic steatohepatitis; physical activity