Effect of Exercise on Hepatic Fat in Overweight Children (EFIGRO)

The objective of the present study is to evaluate the effect of 6 months exercise intervention program on hepatic fat fraction in overweight children. Methodology: A total of 160 children, 9-11 years old, will be randomly assigned to control (N=80) or intervention (N=80) groups. Training sessions will include 90 minutes of exercise, comprising warm-up and skill development. The control group will attend a healthy lifestyle education program (2 days/month) and the intervention group an exercise (3 days/week) and healthy lifestyle education (2 days/month) combined program. Before and after the intervention (6 months) hepatic fat fraction, body composition, , and cardiometabolic risk factors will be measured. Furthermore, dietary habits and physical activity, blood pressure and pubertal development will be evaluated before and after the intervention.

The control group will attend a healthy lifestyle education program (2 days/month) and supportive therapy and behavioral advice for both children and parents to improve nutrition and physical activity (nutritionists and psychologists). The intervention group will attend an exercise (3 days/week) and healthy lifestyle education (2 days/month) combined program. Training sessions will include 90 minutes of exercise, comprising warm-up and skill development, moderate to vigorous aerobic activities, flexibility and strength exercises. Before (baseline) and after the intervention (6 months) total and abdominal adiposity, lean tissue mass and bone mass density (dual-X-ray-absorptiometry), abdominal visceral and hepatic adiposity (magnetic resonance imaging), and blood insulin, glucose, C-reactive protein, alanine aminotransferase, aspartate aminotransferase, gamma-glutamil transpeptidase and lipid profile will be measured. Furthermore, cardiorespiratory fitness (treadmill test) and blood pressure will be measured before and after the intervention. Changes (6 months - baseline) in dietary habits will be estimated by using two repeated 24h recalls and food frequency questionnaires and changes (6 months - baseline) in physical activity by accelerometry.

healthy lifestyle education including healthy lifestyle education, supportive therapy and behavioral advice for both children and parents to improve nutrition and physical activity

multidisciplinary intervention program including healthy lifestyle education, supportive therapy and behavioral advice for for both children and parents to improve nutrition and physical activity and supervised exercise.

Exercise group: The intervention program includes an education program promoting healthy dietary habits and physical activity (nutritionist), supportive therapy and behavioral advice for the family to improve nutrition and physical activity (psychologist) (2 times/month, for children and parents) and supervised exercise (3 times/week, 90 mins) program for 6 months.

Changes in hepatic fat fraction measured by magnetic resonance imaging after the 6 months intervention program

Changes in insulin sensitivu¡ity measured by homeostasis model assessment (HOMA) after the 6 months intervention program

Changes in total, alanine transaminase (ALT), aspartate transaminase (AST) and gamma-GT after the 6 months intervention program

Changes in dietary habits estimated by 24h recall and food frequency questionnaire after the 6 months intervention program

Changes in visceral adipose tissue (MRI), abdominal and total adiposity (DEXA), lean tissue mass and bone mass (DEXA) the 6 months intervention program

Changes in blood pressure, leptin, adiponectin, C-reactive protein (CRP) after the 6 months intervention program

Inclusion Criteria: Overweight or obesity status 9-11 years old Exclusion Criteria: Medical conditions that hamper their participation in the exercise program Secondary obesity

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