Body composition in childhood obesity.
Doctoral thesis, UCL (University College London).
Childhood obesity has been increasing rapidly. Previous work investigating body composition in obese children and adolescents has relied primarily on body mass index (BMI), or on measures that assume constant properties of fat-free mass (FFM). This limits our understanding of the effect of treatment. My PhD is divided into three aims. First, I explored differences in body composition between obese and non-obese children using multi-component models. Second, I investigated the effectiveness of two weight-loss programmes (a randomised controlled trial adopting the traffic-light program (TLP), and a pilot study evaluating treatment using Metformin). Third, I evaluated a bio-electrical impedance analysis (BIA) machine (TANITA BC-418 MA) as a clinical tool for assessing body composition in obese children. Aim 1: obese children had greater hydration of FFM; this limits the accuracy of using techniques that assume constant FFM properties. Taking this into account, obese children had increased fat mass (FM) and FFM, particularly FM in the abdomen region. Aim 2: analyses from the TLP revealed that treatment and control groups significantly lost 0.1 BMI SDS during the trial; but did not significantly differ for any of the body composition outcomes. A further analysis revealed that there was a significant reduction in BMI SDS and FM but an increase in FFM in the period when obese children were treated versus an increase in BMI SDS and FM in the period when they were left. Results from the Metformin programme revealed no significant change in body composition following 6 months or 1 year treatment. Aim 3: using a manufacturer’s equations, TANITA was not accurate at assessing body composition or its change over time. My new equations has no systematic bias in relation to body fatness, although an error of the FFM estimate of 2.2kg, and may be used to guide management in clinical practice.
|Title:||Body composition in childhood obesity|
|Additional information:||Authorisation for digitisation not received|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Child Health|
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