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Abstract
The effectiveness of interventions used in the prevention and treatment of childhood obesity published in a recent issue of Effective Heath Care is reviewed.
- obesity
- children
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This article is based on a recent issue of Effective Health Care which focused on the effectiveness of interventions used in the prevention and treatment of childhood obesity.1
BACKGROUND
Obesity is now considered to be a global epidemic.2 UK research suggests that the prevalence of overweight and obesity amongst children of all ages is increasing.3–5 Estimates of actual figures vary due to an ongoing debate as to how best to measure childhood obesity.6
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.7 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.8,9
Obesity in childhood can cause dyslipidaemia, hyperinsulinaemia, and hypertension.10 Additionally, the first obesity related cases of type 2 diabetes in white adolescents have been reported in the UK.11 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 self-esteem.12,13
Halting the rising prevalence of overweight and obesity in children is a public health priority,14 and there are now a number of government initiatives specifically targeting schools and school children.15–18 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,19 and are forthcoming from the Scottish Intercollegiate Guidelines Network.20
Based upon updated Cochrane reviews,21,22 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.
RCTs evaluating school based programmes
RCTs evaluating the effects of family based interventions
RCTs evaluating the effects of family based behaviour modification programmes
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).23 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.
Physical activity
In the first RCT (n=310), trained staff encouraged infant school classes (mean age 4.5 years) to take part in a 30 week exercise programme.24 At the end of the programme there were no statistically significant differences between children who exercised and those in the control group, although the prevalence of obesity decreased in both groups of children.
The second RCT evaluated a physical education programme (project SPARK) designed to provide high levels of exercise for children in three 30 minute sessions per week over an 18 month period.25 The children in the two exercise groups were led by either specialist PE teachers or classroom teachers. At the end of the programme there were no statistically significant differences in the levels of obesity between those in the exercise group and those in the control group.
Multifaceted interventions
The Active Programme Promoting Lifestyle in schools (APPLES) RCT (n=636) included children aged 7–11 years.26 The programme consisted of teacher training, modification of school meals, the development of school action plans targeting the curriculum, physical education, tuck shops, and playground activities, and was compared with a no intervention control group. Ten primary schools were randomised and at 1 year there was no difference in change in BMI scores between the two groups. The APPLES programme had little effect on children’s eating behaviour other than a modest increase in the consumption of vegetables.
The Kiel Obesity Prevention Study (KOPS) was a primary school based intervention which assessed the additional impact of a family based programme for obese children or normal weight children with obese parents (n=297).27 This RCTexamined the combined effects of dietary education and exercise in which both the children and their parents were instructed to eat fruit and vegetables each day, reduce high fat foods, keep active at least 1 hour a day, and decrease television viewing. Control children received no intervention. At 1 year there were no significant differences in mean BMI scores between the two groups.
A large RCT (n=1295) involving the multi-faceted “Planet Health” programme targeted older children (aged 11–13 years).28 This programme promoted physical activity, modification of dietary intake, and reduction of sedentary behaviours. Control schools received their usual health curricula and physical education classes. After 18 months the prevalence of obesity among girls in the intervention schools was reduced compared with controls (OR 0.47; 95% CI 0.24 to 0.93; p=0.03). In addition, there were fewer obese girls in the intervention group than in the control group (OR 2.16; 95% CI 1.07 to 4.35; p=0.04). The programme significantly reduced television viewing hours for both boys and girls.
A much smaller RCT (n=43) assessed whether a “Dance for Health” programme had a greater impact on increasing aerobic capacity, maintaining or decreasing weight, and improving attitudes towards fitness than usual physical education (n=38).29 At the end of the programme there was a statistically significant decrease in BMI and change in heart rate for girls in the intervention group compared with those in the control group. There were no statistically significant differences between the groups for boys.
Family based interventions (table 2)
Health promotion
In one RCT (n=55) an obesity prevention programme (which stressed the importance of eating a low fat, low cholesterol diet and increasing activity) was compared with a control group that took part in a general health education programme.30 At the end of the 12 week study there was a statistically significant difference in favour of the intervention in terms of the percentage of daily calories from fat.
In a second RCT, 26 families with non-obese children who had obese parents were randomised to groups that encouraged fruit and vegetable intake or decreased intake of high fat/high sugar foods.31 At 1 year follow up there was a significantly greater decrease in percentage overweight in favour of parents in the increased fruit and vegetable group, but no significant between group differences in percentage overweight for children.
A third RCT (n=185) compared two types of intervention (routine general information leaflet versus enhanced information about a specific diet, physical activity, active parental commitment, and food diary) delivered by family paediatricians in primary care (table 2).32 At 1 year follow up, although both intervention groups showed a reduction in percentage overweight from baseline, the reduction was significantly greater in the enhanced information group than in the routine information group.
Physical activity and health promotion
In one RCT (n=53) dietary education was compared with dietary education plus exercise and (for the first s6months only) a waiting list control.33 At 12 months a statistically significant decrease in terms of percentage overweight from baseline was found for both intervention groups, but there were no differences between the two groups. In a second RCT (n=23) comparing dietary education with dietary education plus exercise, statistically significant decreases in percentage overweight from baseline were observed for both groups.34 At 6 months (but not 12 months) follow up the dietary education plus exercise group showed a statistically significant greater reduction in percentage overweight than the diet only group.
A third RCT (n=35) compared a callisthenics group, a lifestyle exercise group, and an aerobic exercise programme.35 All groups also received dietary education. At 24 months the percentage overweight for the lifestyle group was significantly smaller than for the callisthenics and aerobic groups. Analysis at 10 year follow up indicated that children in the lifestyle and aerobic exercise groups had achieved a statistically significant greater reduction in the percentage overweight than those in the callisthenics group.36
Two RCTs (n=61, n=90) compared the effects of increasing physical activity with decreasing sedentary behaviour.37,38 Participants in both studies were also given the “traffic light” diet to follow. At 1 year follow up in the first RCT, all groups (increased exercise, decreased sedentary behaviours or both) had lost weight compared with baseline.37 However, children in the reduced sedentary behaviour group had a statistically significant greater reduction in percentage overweight than the other groups. In the other RCT all groups (high or low increased physical activity, high or low decreased sedentary behaviours) showed significant decreases in percentage overweight at 6 and 24 months compared with baseline.38 However, the differences between the groups were not statistically significant.
Behaviour modification programmes (table 3)
Parents as agents of change
In one RCT (n=33) overweight children (aged 8–12 years) and their parents were assigned to a multi-component behavioural “weight reduction only” programme, a parent training programme involving the same multi-component weight reduction behavioural treatment preceded by a short course for the parents in child management skills, or a waiting list control.39 At 1 year follow up, while both intervention groups gained weight, there was a statistically significant increase in percentage overweight in the weight reduction only group compared with the parent training group.
In the SHAPEDOWN programme, parents were instructed on strategies for supporting the weight loss efforts of their children, including altering family dietary and activity patterns and improving parenting and communication skills.40 At 15 month follow up, participants in the intervention programme (n=37) had statistically significant decreases in relative weight compared with a no-intervention control group (n=29).
Another RCT (n=39) evaluated the effects of targeting obese children and their parents for mastery of diet, exercise, weight loss, and parenting skills over 2 years.41 A control group was taught general strategies for changing behaviour. At 6 and 12 months follow up, children in the intervention group had a statistically significant relative weight reduction compared with controls. These results were not maintained at 2 years.
The final RCT (n=60) examined the effects of parents taking responsibility for their children’s behaviour change compared with the conventional approach in which children were responsible for their own weight loss.42 At 1 year follow up, children in both groups showed a significant decrease in obesity, although there was a statistically significantly greater reduction in the parent-led intervention group.
Family based behaviour modification programmes
One RCT (n=42) compared three methods of involving (or not involving) mothers (mother-child separately, mother-child together, and child alone) in the treatment of their obese adolescents.43 The intervention programme consisted of behaviour modification, social support, diet, and exercise. At 1 year follow up, the “mother-Child separately” group had lost significantly more weight and showed greater reductions in percentage overweight than the other two groups which, in turn, did not differ from each other.
A second trial (n=40) compared behavioural treatment groups (parent plus child, child only) with a waiting list control group.44 Children in both behavioural groups lost weightduring the intervention and maintained their losses through the 1 year follow up period. No statistically significant differences were found between the behavioural treatment groups.
The third trial (n=45) compared the rapid and gradual scheduling of a behavioural programme with a non-specific control and a waiting list control group.45 At 6 month follow up the behavioural interventions showed significantly greater reductions in absolute weight loss and percentage overweight than the non-specific control. No statistically significant differences were found between the rapid and gradual scheduling groups.
In another study, 43 children were randomised to receive either conventional treatment or family therapy as an adjunct to conventional treatment.46 A further 50 non-randomised obese children were included in a control group that received no intervention. At 12 month follow up the BMI scores of all three groups increased, although there was a statistically significant smaller increase in BMI scores in the family therapy group than in the untreated control group. No statistically significant differences were found between the two intervention groups.
In an Australian RCT (n=27), overweight children (aged 7–13 years) and at least one parent were randomly assigned to either behavioural management plus relaxation placebo or a combined behavioural-cognitive self-management approach.47 At 3 and 6 month follow ups there was a statistically significant reduction in percentage overweight for children in both groups compared with baseline. There were no statistically significant differences between the groups at either 3 or 6 months follow up.
Another RCT compared four different behaviour modification programmes (summer camp training, advice in a single session, group outpatient, individual outpatient) for obese children against a control group.48 However, the only participants who were randomised were those allocated to the two outpatient programmes (n=93). A statistically significant reduction in mean percentage overweight was found at 6 and 12 months follow up for both outpatient groups compared with baseline. However, there were no statistically significant differences between the two groups.
A 6 month family based behavioural weight control programme (n=67 families) compared parent and child problem solving, child problem solving, and “standard” family based treatment (no problem solving).49 Over 24 months follow up the “standard” group had a larger decrease in BMI than the parent and child group.
Finally, 31 families with obese children were randomised to receive “mixed” behavioural treatment (a mixture of individualised plus group therapy) or “group” behavioural treatment (that did not involve individual therapy).50 At 12 months follow up, both treatments produced a statistically significant reduction in percentage overweight and BMI compared with baseline. However, there were no significant differences between the groups.
Behaviour modification with no parental involvement
One RCT (n=197) of a 6 week inpatient rehabilitation programme for children and adolescents compared a three part cognitive-behavioural programme with a programme that provided muscle relaxation training.51 Both intervention groups received the same diet and exercise programme. In both groups the percentage overweight was significantly reduced over the course of 1 year compared with baseline. Differences between the groups were not statistically significant.
Pharmacological interventions
One RCT examined the effects of metformin on BMI, serum leptin, glucose tolerance, and serum lipids in 29 obese young people aged 12–19 years with fasting hyperinsulinaemia and a family history of type 2 diabetes.52 At the end of the 6 month study a statistically significant difference (p<0.02) was found between the BMI scores for the intervention group (BMI decreased) compared with the placebo group (BMI increased).
The National Institute of Clinical Excellence (NICE) has approved the use of two drugs, orlistat and sibutramine, in the management of adult obesity.53,54 However, there is no guidance for the use of these agents in children. An RCT trial of the use of orlistat in obese 12–17 year olds funded by the US National Institute of Child Health and Human Development is currently ongoing.55
IMPLICATIONS
There is a lack of good quality evidence on the effectiveness of interventions on which to base national strategies or to inform clinical practice. Trials are often small in size, have high drop out rates, are poorly reported, and crucially involve settings that may be difficult to translate to the UK. Additionally, many of the interventions have been evaluated in only one or two studies and most of the research has been conducted in North America. Many of the studies recruited children either through existing specialist obesity centres or media advertisements. As such, results from these studies may not be applicable to children and their families in other settings.
Future research must be of good methodological quality, involve large numbers of participants in appropriate settings, and needs to be of longer duration and intensity. The cost effectiveness of obesity related prevention and treatment needs to be addressed.
There are now a number of government initiatives specifically highlighting the key role that schools can play in improving the health of children. There is some evidence that multifaceted school based programmes that promote physical activity, the modification of dietary intake, and the targeting of sedentary behaviours may help to reduce obesity in school children, particularly girls.
Multifaceted family based programmes that involve parents, increase physical activity, provide dietary education, and target reductions in sedentary behaviour may help children to lose weight.
There is some evidence that family based behaviour modification programmes, where parents take primary responsibility and act as agents of change, may help children to lose weight.
Acknowledgments
The following CRD staff (in alphabetical order) comprised the Effective Health Care childhood obesity review team: Christopher Bridle, Sarah King, Lisa Mather, Mark Rodgers, Nancy Rowland, Frances Sharp, Amanda Sowden and Paul Wilson.