Interrelationship between Obesity, Physical Fitness, Sedentary Time, and Childhood Asthma: meta-analysis and cohort study
Date Issued
2014
Date
2014
Author(s)
Chen, Yang-Ching
Abstract
The dissertation includes a meta-analysis of childhood obesity in prediction of incident asthma and a cohort study exploring interrelationships between obesity, physical fitness, sedentary time, and childhood asthma. Aim of meta-analysis were to quantify the risk of childhood obesity on incident asthma. The following two studies were to compare various anthropometric measures of obesity in relation to childhood asthma, and to further characterising the interrelations amongst central obesity, physical fitness level, sedentary time, and asthma.
Study I: Childhood Overweight and Obesity Predict the Risk of Incident Asthma: Meta-analysis
Aims of our meta-analysis were: (1) to quantify the predictability of childhood overweight and obesity on the risk of incident asthma; (2) to evaluate the gender difference on this relationship. The selection criteria were including prospective cohort pediatric studies which use age and sex-specific BMI as a measure of childhood overweight and the primary outcome of incident asthma. A total of 1027 studies were initially identified through online database searches, and finally 6 studies met the inclusion criteria. The combined result of reported relative risk from the 6 included studies revealed that overweight children conferred increased risks of incident asthma as compared with non-overweight children (relative risk, 1.19; 95% CI, 1.03-1.37). The relationship was further elevated for obesity versus non-obesity (relative risk, 2.02; 95% CI, 1.16-3.50). A dose-responsive of elevated BMI on asthma incidence was observed (p for trend, 0.004). Obese boys had a significantly larger effect than obese girls (relative risk, boys: 2.47; 95% CI, 1.57-3.87; girls: 1.25; 95% CI, 0.51-3.03), with significant dose-dependent effect. Proposed mechanisms of gender difference could be through pulmonary mechanics, sleep disordered breathing, and leptin. Further research might be needed to better understand the exact mechanism of gender difference on the obesity-asthma relationship.
Study II: Comparing various different anthropometric measures in relations to asthma and the role of physical fitness/sedentary time in the link between obesity and asthma
UAvailable prospective study on obesity and asthma used only body mass index as an indicator of adiposity. Studies using more detailed obesity measurements such as waist to height ratio, or lean body mass are lacking.
In 2010, we conducted a nationwide “Taiwan Children Health Study (TCHS) ”, of 2,758 ten-years-old school children in 14 Taiwanese communities. They were followed up annually from 2010-2012. Our annual follow-up items were parent’s and children’s health questionnaires, BMI, abdominal/hip circumference, skin fold thickness, body composition, physical fitness and sedentary time (2010 and 2012), and pulmonary function tests. All anthropometric measurements were standardized. Sedentary time was assessed by Chinese version of the international Physical Activity Questionnaire (IPAQ-C). Physical fitness tests were performed through standardized protocol by our Education bureau in each school during our follow ups survey. Amongst these tests, an 800-metre sprint was used to determine the cardiorespiratory endurance of each child, which was most likely relevant to both obesity and asthma. Childhood asth ma was defined according to active asthma and physician-diagnosed asthma in the parent’s questionnaire. The generalized estimating equation (GEE) was used for three years of repeated measurements to analyse the interrelation amongst obesity, sedentary time, physical fitness level, and asthma.
Central obesity is the best predictor for active asthma and physician-diagnosed asthma, with significant dose responsiveness. Low physical fitness levels and high screen time were associated with increased risk of central obesity, but was not significantly related to childhood asthma.
Study III: Exploring the interrelationships between central obesity, physical fitness/sedentary time, and asthma in Structual Equation Model (SEM).
A structural equation model (SEM) was used to explore the pathogenesis amongst central obesity, physical fitness/sedentary time, and asthma. Asthma incidence was analysed during a 2-year follow-up amongst centrally obese and non-obese groups in baseline non-asthmatic children. Moreover, according to previous literature, one possible biological mechanism from central obesity to asthma could be mediated by poor pulmonary function. Therefore, we also aim to examine the role of pulmonary function between central obesity and childhood asthma.
Through three different kinds of statistical analysis, we found that physical fitness/sedentary time were not intermediate factor between central obesity and asthma. In the pathway from central obesity to childhood asthma, physical fitness and sedentary time are leading factors. Physical fitness levels and sedentary time indirectly influence asthma risk. Obesity-related reduction in pulmonary function is a possible mechanism in the pathway from central obesity to asthma.
Conclusively, we discovered that incident asthma risk was increased by 20 % in overweight children. Boys, rather than girls suffered from significantly higher risk in the obesity-asthma relationship. Central obesity measures most accurately predict asthma and should be incorporated in childhood asthma risk predictions. Children are encouraged to increase their physical fitness levels and reduce their sedentary time to prevent central-obesity-related asthma.
Subjects
腹部肥胖
體適能
靜坐時間
肺功能
氣喘
發生率
結構方程式
SDGs
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-103-F97846002-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):a460a3ace1a983d435b8d573bd4e5572