EFFECTIVENESS BULLETIN The prevention and treatment of childhood obesity

BACKGROUND Obesity is now considered to be a global epidemic. UK research suggests that the prevalence of overweight and obesity amongst children of all ages is increasing. Estimates of actual figures vary due to an ongoing debate as to how best to measure childhood obesity. There is considerable debate around the reasons for the increasing prevalence of childhood overweight and obesity. Possible explanations include an increase in sedentary lifestyles and changes in dietary patterns and eating habits. Among adults it appears that average recorded energy intake in Britain has declined substantially as obesity rates have escalated, which may suggest that sedentary lifestyles are an important factor. 9 Obesity in childhood can cause dyslipidaemia, hyperinsulinaemia, and hypertension. Additionally, the first obesity related cases of type 2 diabetes in white adolescents have been reported in the UK. Overweight and obesity are also known to have a significant impact on psychological wellbeing with many children developing a negative self-image and experiencing low selfesteem. 13 Halting the rising prevalence of overweight and obesity in children is a public health priority, and there are now a number of government initiatives specifically targeting schools and school children. Additionally, guidelines on the weight management of children and adolescents in primary care have been published by the Royal College of Pediatrics and Child Health in conjunction with the National Obesity Forum, and are forthcoming from the Scottish Intercollegiate Guidelines Network. Based upon updated Cochrane reviews, 22 this paper focuses on the effectiveness of interventions in the prevention and treatment of childhood obesity. The Cochrane review on prevention included non-randomised studies, but this paper focuses exclusively on randomised controlled trials (RCTs). Only studies with over 20 participants have been reported in the text, but the results of all 35 included RCTs are reported in tables 1–3. EFFECTIVENESS School based programmes (table 1) Health promotion One school based RCT (n=227) assessed the effects of using a classroom based curriculum to reduce television, videotape, and video game use on changes in physical activity, dietary intake, and obesity (adiposity). At 7 months follow up the children in the intervention group (n=106) were found to watch significantly less television and to play fewer video games than children in the control group. Children in the intervention group also had statistically significant decreases in body mass index (BMI), triceps skinfold thickness, waist circumference, and waist to hip ratio compared with the control group.