Epidemiology of childhood obesity
In recent years awareness of childhood obesity as a clinical and public health problem has increased. However, a number of important issues related to childhood obesity were unclear when this thesis began. The aims of this thesis were as follows: 1. To estimate the prevalence of obesity in British and Iranian children. 2. To assess the strengths and weaknesses of the body mass index (BMI) as a way of identifying obese children/estimating obesity prevalence. 3. To investigate the factors associated with early 'adiposity rebound'. 4. To identify risk factors for obesity in British children. This thesis showed that prevalence of childhood obesity in British and Iranian children was significantly higher than expected and that obesity prevalence in children increased during the 1990s. These results are consistent with reports of increased childhood obesity in the USA, Europe, and some other countries. Using BMI 95th centile as the definition of childhood obesity has moderately high sensitivity and high specificity, though a definition of BMI 92nd centile was shown in this thesis to be optimum. This thesis indicated that the typical age of AR in British children must be sometime between 5-7 years. Further research on the factors associated with timing of AR is recommended. A number of independent risk factors for childhood obesity are identified. Parental obesity, birth weight, fizzy drink consumption, and time spent in the car had the strongest association.