Exercise intervention in overweight and obese adolescents: Meta-analysis and implications for New Zealand

Abstract

Background: The global rise in the prevalence of childhood and adolescent obesity has been linked to modifiable lifestyle factors, including lack of physical activity. However, no known meta-analysis has been conducted on the effects of exercise intervention on weight loss and metabolic risk factors in overweight and obese adolescents. Objectives: To investigate whether exercise intervention improves body composition and cardio-metabolic risk factors in overweight and obese adolescents. Data Sources: PubMed, Web of Science, SPORTDiscus, Google Scholar. Study Selection: randomized controlled trial; structured exercise intervention, alone or combined; control group received no other treatment designed to increase physical activity; participants were overweight or obese; and aged between 10 and 19 years. Appraisal and Synthesis Methods: 1667 studies were identified. After evaluation of study characteristics and quality and validity, data from 13 studies (15 trials) involving 554 participants were extracted for meta-analysis. Results: Following exercise intervention, there was a most likely moderate reduction in BMI (2.0, CI: 1.5, 2.5). There were also most likely small reductions in body weight (3.7 Kg, CI: 1.7, 5.8), body fat percentage (3.1 %, 95% CI: 2.2, 4.1), waist circumference (3.0 cm, CI: 1.3, 4.8), and a most likely trivial increase (improvement) in lean mass (1.6 Kg, 95% CI: 0.5, 2.6). Following an oral glucose tolerance test, there was a most likely large improvement in the area under the curve for insulin (162 μU/ul, 95% CI: 93, 231) and very likely moderate improvement in blood glucose (39 mg/dl, 95% CI: 9.4, 69). There were also most likely moderate improvements in the homeostatic model assessment (1.0, 95% CI: 0.7, 1.4) and systolic blood pressure (7.1 mm Hg, CI: 3.5, 10.7). The effects of exercise on total cholesterol, LDL cholesterol, HDL cholesterol, fasting insulin and fasting blood glucose were inconclusive. Conclusions: The current evidence suggests that exercise intervention in overweight and obese adolescents improves body composition, including decreased body fat and increased lean muscle mass. The limited available evidence further indicates that exercise intervention improves cardio-metabolic risk factors.