Introduction: The increased survival rates of children with brain tumors is the result of decades of advancement in diagnostic and therapeutic approaches, but brought the adverse long-term effects of the treatments and tumors on these children into focus. Survivors of childhood brain tumors (SCBT) are at an increased risk of cardiometabolic disorders and premature mortality. Obesity and excess adiposity are well-established risk factor for cardiometabolic risk in the general population, but its contribution to these outcomes in survivors is unknown. More recently, adiposity has emerged as a more robust predictor of cardiometabolic risk than body mass index, the most clinically used measure of obesity. The current thesis pursued four objectives: 1) to determine the prevalence of obesity and excess adiposity in SCBT 2) to explore adiposity and its determinants in SCBT 3) to investigate the determinants of obesity in SCBT and 4) to identify potentially effective interventions to manage obesity in SCBT.
Methods: Systematic reviews and meta-analyses were used to evaluate the prevalence and interventions for overweight and obesity in SCBT while the determinants of adiposity and obesity were explored using primary data and regression analyses. General health information and brain tumors information were collected with standardized questionnaires and review of medical records. The overweight or obesity status of subjects was determined by body mass index (BMI), and adiposity profile was evaluated using percent body fat (%FM), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR).
Results: The results show no difference between the overweight and obesity rates in SCBT and non-cancer controls. However, SCBT have higher total and central adiposity. Birth weight is found to be a predictor of future BMI in SCBT, while a higher total adiposity in SCBT is predicted by having supratentorial tumors and receiving radiotherapy. Lastly, not enough evidence is available to conclude the effectiveness of lifestyle interventions, pharmacotherapy, and bariatric surgery on managing obesity in SCBT.
Conclusions: Obesity, determined by BMI, is not enough to determine cardiometabolic risks in SCBT. Total and central adiposity should be measured as well to identify high-risk group. Special attention should be paid to SCBT with high birth weight, supratentorial tumors, and having received radiotherapy. Lastly, more randomized controlled trials are needed to provide high-quality evidence to determine the effectiveness of interventions to manage obesity and improve outcomes in SCBT. / Thesis / Master of Science (MSc) / Brain tumors are the most common solid tumors in children. The survival rates among children with brain tumors have increased significantly over the past four decades due to advances in early detection and treatment. However, these children are at increased risk of heart disease and type 2 diabetes, and early death. Evidence has suggested obesity and excess body fat as main reasons for cardiometabolic disorders in the general population, but it is not known if obesity and excess body fat contribute to diabetes and heart disease in survivors. Therefore, the current thesis aims to explore obesity and adiposity, their predictors and any existing treatments available to survivors of childhood brain tumors (SCBT) to see if outcomes can be improved.
The results show that while survivors of childhood brain tumors have similar overweight and obesity rates to the general population when measured by the most common clinical measure, called body mass index (BMI), they in fact have higher fat mass. Furthermore, we identified birth weight as a predictor of obesity while the location of the tumors and receiving radiation therapy as predictors of the fat mass in SCBT. The results also show the lack of current effective interventions to manage obesity in SCBT. This data is critical to consider in the design and implementation of strategies to reduce heat disease and diabetes in survivors to improve their quality of life and lifespan.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22205 |
| Date | 16 November 2017 |
| Creators | Wang, Kuan-Wen |
| Contributors | Samaan, M. Constantine, Medical Sciences |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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