- Title
- Paediatric obesity, inflammation & asthma
- Creator
- Jensen, Megan Elizabeth
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2013
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Obesity and asthma are the most common conditions affecting the paediatric population worldwide, with obesity being more prevalent in the population with asthma. Obesity in children with asthma is associated with increased asthma symptoms, increased number and severity of exacerbations, and increased use of medications, including inhaled corticosteroids. With the advent of obese asthma, occurring in parallel with Westernisation, the role of obesity and associated metabolic and lifestyle factors in the development and/ or pathogenesis of asthma, and in asthma management, have been called into question. Although obese asthma has been described in the adult population as a distinct clinical phenotype, characterized by neutrophilic airway inflammation, reduced static lung function and corticosteroid resistance, there has been minimal research on obese asthma in the paediatric population. The current thesis aims to characterise the inflammatory, physiological and clinical aspects of obese asthma in children; to understand the prevalence of risk factors for weight gain in children with asthma; and to investigate the feasibility and efficacy of dietary intervention to induce weight loss and improve asthma outcomes in paediatric obese asthma. Chapter III presents the airway and systemic inflammatory profile, dynamic and static lung function, and clinical asthma outcomes in obese and non-obese children, with and without asthma. In this cross-sectional study, we found a poorer quality of life and reduced static lung function (expiratory reserve volume (ERV)) in obese asthmatic children. Sputum %eosinophils and the prevalence of eosinophilic asthma was lower in obese females compared to obese males, indicating that the female gender may be associated with a different pattern of airway inflammation in obese asthma. This is important to asthma management and requires further investigation. However, the overall airway and systemic inflammatory profile did not differ between obese and non-obese asthmatic children. In Chapter IV, the associations between lung function and body composition in children, with and without asthma, were explored. Body weight, fat mass and lean mass were inversely associated with static lung function (functional residual capacity (FRC) and ERV), suggesting that obesity, regardless of composition, is associated with reduced static lung function. Conversely, lean mass was positively associated with improvements in dynamic lung function. This study indicates that it is important to consider body composition as fat and lean mass, which both increase with obesity, may have differential effects on lung function. Chapter III and IV demonstrate that obesity is associated with lung deficits that are not detectable through routine spirometry. This suggests that in clinical practice static lung function needs to be routinely measured in obese asthmatic children. In Chapter V, the presence of key modifiable risk factors for weight gain were compared in a cross-sectional study of non-obese children, with and without asthma, including sleep architecture, appetite and dietary intake, and physical and sedentary behaviour. Sleep latency was extended, and triglyceride levels were higher, in children with controlled asthma compared to non-asthmatic children. This study did not detect differences in plasma appetite hormone concentrations, food cravings, dietary intake or physical activity levels. However, in this group of asthmatic and non-asthmatic children, daytime sleepiness and reduced sleep duration were associated with adverse changes in plasma lipids, dietary patterns and sedentary behaviour, which can potentially lead to positive energy balance and warrants further investigation. In Chapter VI, the feasibility and efficacy of a ten week dietary intervention to induce acute weight loss in a group of obese children with asthma was demonstrated in a pilot randomised controlled trial. Dietary intervention induced statistically significant acute weight loss in asthmatic children, with improvements in asthma control and static lung function. This indicates that dietetic consultation is beneficial and should be integrated as part of the management of the obese child with asthma. The research conducted as part of this thesis has contributed to the understanding of paediatric obese asthma; investigated the prevalence of key lifestyle risk factors for obesity in asthmatic and non-asthmatic children; and provided pilot data to support the efficacy of dietary-induced weight loss to improve asthma outcomes in obese asthmatic children.
- Subject
- asthma; paediatric; obesity; pediatric; respiratory; body mass index; body composition; inflammation; nutrition; diet
- Identifier
- http://hdl.handle.net/1959.13/937210
- Identifier
- uon:12524
- Rights
- Copyright 2013 Megan Elizabeth Jensen
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Abstract | 491 KB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Thesis | 2 MB | Adobe Acrobat PDF | View Details Download |