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The effectiveness of a school-based programme to reduce obesity

 

The rapidly increasing prevalence of obesity has prompted research into ways of preventing obesity, particularly among children. Schools offer a potentially ideal channel for communicating a preventive programme. This study examines the effectiveness of a school-based intervention programme to reduce obesity in children.

Message

Very interestingly, the programme successfully reduced obesity in girls, but not in boys, highlighting the need for research to investigate whether girls and boys need different approaches for tackling obesity. This study also highlights the need for much more research in the design and implementation of successful school programmes to reduce obesity. It also adds further evidence that reducing television viewing has an important role to play in reducing overweight in children.

Reference

SL Gortmaker et al. Reducing obesity via a school-based interdisciplinary intervention among youth. Archives of Pediatric Adolescent Medicine 1999 153: 409-418.

Study

In 1995, ten schools were randomly assigned to participate either in an intervention programme (Planet Health) or not (the comparison programme). The 1,295 children who participated were 11 years old, from ethnically diverse backgrounds and 48% were girls. The prevalence of obesity was 27% in intervention students and 28% in comparison students.

Planet Health was designed to reduce obesity by improving physical activity and dietary behaviours of all students (without singling out those who were obese). The programme, which was incorporated into the existing curricula, targeted four behavioural changes: reducing television viewing to less than two hours a day, increasing physical activity, decreasing consumption of high fat foods and increasing consumption of fruit and vegetables to at least five servings a day.

Information was collected at the beginning of the study and two years later. The primary measurement was obesity, defined by both body mass index (kg/m2) and a triceps skinfold thickness (greater than or equal to the 85th percentile). Three aspects of obesity were measured: its prevalence; its reduction among those already obese; and the prevention of new cases. Secondary measurements were television viewing, physical activity, percentage of total dietary intake from fat, servings of fruit and vegetables and total energy intake, all of which were assessed with questionnaires.

Results

Obesity

Obesity prevalence among female students receiving the programme reduced compared with female students not receiving the programme (odds ratio 0.47, 95% confidence interval 0.24 to 0.93).

There was a greater reduction of obesity among female students receiving the programme compared with those not receiving the programme (odds ratio 2.16, 95% confidence interval 1.07 to 4.35).

There were no differences in the prevention of new cases among girls and no differences among boys in obesity prevalence, reduction or prevention.

Behaviours

The number of television hours a day was reduced among both girls and boys receiving the programme compared to those not receiving it (girls: -0.58 hours, 95% confidence interval -0.85 to -0.31; boys: -0.40 hours, 95% confidence interval -0.56 to -0.24).

The only other behaviour to change over the two years among girls and boys was an increase in fruit and vegetable consumption seen among girls receiving the programme (0.32 servings/day, 95% confidence interval 0.14 to 0.50).

Comment

Interestingly, this school-based programme was successful in reducing obesity among girls, but not among boys. This suggests that different approaches need to be considered for girls and boys in the reduction of obesity. This would make for some very interesting research.

The role of television in reducing obesity presents itself again and adds credence to the importance of reducing television viewing among children.

Of the other behaviours measured, only fruit and vegetable consumption among girls receiving the programme increased, highlighting the difficulties of designing, implementing and evaluating school-based programmes. School-based programmes need to be simple, easy to implement and they need to motivate students (and over the long term and not just while the programme is being taught). Much more research is needed to investigate ideal programme designs for different student populations (e.g. students from different socio-economic backgrounds). As Bandolier has said before, school programmes are tricky to evaluate because the results could be affected by many factors, for example their design, how well they are implemented and how many children attend the classes.