Obesity and Insulin Resistance in Adolescents

Abstract

The aim of this thesis is to contribute to the evidence base of knowledge regarding the management of obesity and insulin resistance in adolescents, with a special focus on cardio-metabolic risk factors and vascular health. This thesis commences with two systematic reviews with meta-analyses which, for the first time: 1), summarises the effects of lifestyle interventions, involving diet and physical activity, with/without behavioural modification, on cardio-metabolic outcomes in overweight and obese children and adolescents and 2) assesses whether diet-only interventions are more effective than diet-plus-exercise interventions or exercise-only interventions on both weight loss and cardio-metabolic risk reduction. The second section of this thesis reports the results from a cross-sectional study which compared arterial elasticity (measured by the diastolic pulse contour analysis) between adolescents with pre-diabetes and/or clinical insulin resistance (IR group), adolescents with type 1 diabetes, and age-matched (10-18 year old) healthy controls. The IR group was followed for 12 months to examine the effect of fat loss induced by a lifestyle intervention with metformin therapy (RESIST trial) on arterial elasticity and markers of inflammation. This thesis also reports for the first time the medium-term impact of a prescriptive dietary intervention on dietary restraint, external and emotional eating in obese adolescents with clinical insulin resistance.