The epidemic of childhood obesity: what role do schools play in primary prevention?

The term 'epidemic' is widely used to describe the impact of the growing prevalence of obesity in many countries (1). Initially a problem in adults in westernised countries, obesity has now become an issue in many developing countries, and is increasingly prevalent in child and adolescent populations.

A recent Report to the World Health Organization from the International Obesity TaskForce entitled 'Obesity in children and young people: A crisis in public health' has shown that the worldwide prevalence of overweight (including obesity) in people aged five to 17 years is approximately 10%, with that of obesity alone being two to three percent (2). However, certain regions and countries have particularly high rates of paediatric obesity. For example, more than 30% of children and adolescents in the Americas, and approximately 20% of those in Europe, are overweight or obese.

The rising trend of paediatric obesity in Australia is also well documented. Several Australian studies performed in the mid-1990s have documented overweight and obesity prevalence rates of between 1:5 and 1:4 in children and young people (3,4). It is very probable that, in the first decade of the twenty-first century, obesity, together with its milder version of overweight, has become the most common chronic disease in Australian children and young people.

Unfortunately, paediatric obesity is not a benign condition. The most common consequences are those related to impairment in psychosocial functioning, but orthopaedic, respiratory, gastrointestinal, sleep and metabolic complications are also well recognised during childhood or adolescence (2,5). Long-term complications of child and adolescent obesity include tracking of obesity and metabolic complications through to adulthood, with all the attendant health consequences, as well as an increased risk of premature death and increased morbidity from cardiovascular and other diseases in mid- to late-adulthood.

Thus, child and adolescent obesity is common and is also associated with very significant health complications. For these reasons, it is important that effective prevention strategies are identified and put into place. However, what constitutes an appropriate intervention? A recent Cochrane Review on the prevention of obesity in children reviewed a number of largely school-based interventions and concluded that there are 'limited high quality data on the effectiveness of obesity prevention programs' (6). Not surprisingly, the authors highlighted the need for well-designed studies examining a range of interventions. This view was reiterated in a 'review of reviews' on public health interventions for chronic disease by an interuniversity team from the city of Hamilton, Ontario, Canada (7). This Hamilton Review focused upon school-based interventions and noted that schools were 'an ideal setting for primary prevention interventions in children' due to the large numbers of children enrolled and the long-term contact that schools have with children over several years. Effective school-based health promotion interventions in healthy nutrition, increased physical activity or healthy weight were found to include the following elements: environmental change, multifaceted programs and a behavioural focus (7).

If schools are increasingly to be seen as a setting for primary prevention of obesity, then what are the attitudes of the school community towards this? In this issue of Nutrition & Dietetics, two separate studies address issues relevant to obesity prevention in schools in Australia. Their findings should help inform research on, and policy for, childhood obesity prevention.

Cleland et al. (8) undertook an exploratory study of 12 selected primary schools in Victoria with the aim of determining the types of foods purchased at school canteens, and the perceptions held about school canteens by children, parents and teachers. Most of the relevant teachers participated in the questionnaire survey, but there was a relatively poor ('average') response rate (approximately 40%) from children in Grades 5 and 6 and their parents. Despite this, and the fact that it was not a representative survey, some valuable information was obtained. Children reported purchasing less healthy foods, such as pasties, pies, sausage rolls, lollies and potato crisps, far more frequently than they did fruit and vegetables--by no means an encouraging finding, but hardly surprising. The survey results suggest that poor nutrition knowledge was not a barrier for children making healthy food choices from the school canteen; rather, children reported that unhealthy food alternatives were preferable ('tastier') to healthy food choices, and that there were few healthy foods available in their canteen. Interestingly, when asked what would help them choose healthy foods at their school canteen, the surveyed children gave a number of thoughtful suggestions: greater availability of, and publicity for, the healthy foods and a reduction in cost of the foods. Such strategies are already well recognised in the food marketing and health promotion literature (9).

The parents and teachers in the study tended to agree that the school canteen has a role in promoting healthy food and drink choices. However, compared with parents, teachers had slightly stronger beliefs that the school canteen reinforced nutrition education and acted as a role model for children. Only about 40% of both parents and teachers felt that school canteens were very important in developing children's eating patterns.

The study by Sutherland et al. (10) included a cross-sectional sampling of one large primary school (Kindergarten to Year 6) on the central coast of New South Wales. A high prevalence of overweight (26%) and obesity (12%) was found, but it is impossible to know how typical of Australian children in general this prevalence rate is, until results from more representative surveys are available. The most important findings from the study were the surveyed attitudes of parents, teachers and health professionals. All groups felt that traditional elements of the school curriculum were important in promoting health, providing healthy eating messages and in encouraging children to be physically active. However, there was a mismatch between health professionals and parents and teachers in their attitudes towards the role of the school in obesity prevention. Compared with the other two groups, health professionals tended to more strongly believe that schools have a major role in obesity prevention, that schools should have policies about what children should and should not eat when at school, and that schools should be restricted to selling only healthy foods. Health professionals were also more likely to disagree that only the family is responsible for the food habits of their children or for encouraging children to be more active.

So what can we learn about the attitudes of the broad school community towards primary school-based obesity prevention from these two studies? Firstly, the traditional school curriculum is certainly seen as important for promoting healthy eating and activity. Thus, strategies to support and improve these aspects of the school curriculum are likely to be well accepted by schools, or at least by schools similar to those surveyed in the studies. Plans for modifying or strengthening school curricula are already incorporated in various governmental plans for obesity prevention (11,12). In order to be sustainable in the long term, however, adequate resourcing will be required for such things as the professional development of classroom teachers, the provision of specialised physical education teachers for primary schools and the provision of play equipment and play spaces in schools.

Secondly, there are likely to be differences in attitudes between parents, teachers and health professionals about the role of the school and the school canteen in health promotion and obesity prevention. To give an extreme example, health professionals may be more prescriptive in their attitudes towards school canteens, teachers potentially more cynical about healthful changes being possible, and parents not overly concerned about the impact of school canteens on the health of children! These differing views need to be recognised when developing policies around school canteens and school-based health promotion; otherwise, there is a potential for divergent expectations and miscommunication. The health promoting schools model, which offers a comprehensive approach to health promotion in the school setting, based upon the principles of equity and empowerment, provides a framework where such approaches could be clarified (13).

Schools can play an important role in obesity prevention. However, as highlighted by Swinburn et al. (14), the factors promoting the development of child and adolescent obesity are operating at many levels. Both micro-environmental settings (that is, where individuals live, eat, play or go to school) and macro-environmental settings (that is, the broader sectors that ultimately influence dietary intake and physical activity and which are beyond the ability of an individual to influence) need to be considered. When these are examined, it is apparent that, in addition to schools, there is a range of other potential strategies and settings for primary prevention of obesity in a given community, such as the following:

* regulation of the nature and amount of food advertising directed at children;

* provision of economic incentives for the production and distribution of vegetables and fruit;

* development of town planning and urban transport policies which promote safe, active transport or public transport over motorised transport;

* provision of high-quality recreation areas; and

* improvement in public transport.

Several of the above examples are controversial, politically challenging or resource intensive. However, if we are to be serious about the primary prevention of obesity, then the significant infrastructural barriers to healthy eating and activity in our community, particularly as they affect children and young people, will need to be tackled. This is a challenge for all involved in public health research, policy or practice.

(See papers by Sutherland et al., pages 137-144 and Cleland et al., pages 145-150)

References

1. World Health Organization. Global Strategy on Diet, Physical Activity and Health. Obesity and overweight. www.who.int/dietphysicalactivity/publications/facts/obesity/en/. Accessed 12 August 2004.

2. Lobstein T, Baur L, Uauy R (editors). Obesity in children and young people: A crisis in public health. Report of the International Obesity TaskForce Childhood Obesity Working Group. Obesity Reviews 2004;5 Suppl 1:4S-104S.

3. Magarey AM, Daniels LA, Boulton TJ. Prevalence of overweight and obesity in Australian children and adolescents: reassessment of 1985 and 1995 data against new standard international definitions. MJA 2001;174:561-4.

4. Booth ML, Wake M, Armstrong T, Chey T, Hesketh K, Mathur S. The epidemiology of overweight and obesity among Australian children and adolescents, 1995-7. Aust N Z J Pub Health 2001;26:371-4.

5. Ebbeling CB, Pawlak DB, Ludwig DS. Childhood obesity: public-health crisis, common sense cure. Lancet 2002;360:473-82.

6. Campbell K, Waters E, O'Meara S, Kelly S, Summerbell C. Interventions for preventing obesity in children (Cochrane Review). In: The Cochrane Library, Issue 3, Chichester, UK: John Wiley & Sons Ltd: 2004.

7. Micucci S, Thomas H, Vohra J. The effectiveness of school-based strategies for the primary prevention of obesity and for promoting physical activity and/or nutrition, the major modifiable risk factors for type 2 diabetes: a review of reviews. The Effective Public Health Practice Project, March 2002. http://www.city.hamilton.on.ca/PHCS/EPHPP/Research/Full-Reviews/Diabetes-Review.pdf. Accessed 12 August 2004.

8. Cleland V, Worsley A, Crawford D. What are grade 5 and 6 children buying from school canteens and what do parents and teachers think about it? Nutr Diet 2004:61:145-50.

9. Hannan P, French SA., Story M, Fulkerson JA. A pricing strategy to promote sales of lower fat foods in high school cafeterias: acceptability and sensitivity analysis. Am J Health Prom 2002;17:1-6.

10. Sutherland R, Gill T, Binns C. Do parents, teachers and health professionals support school based obesity prevention? Nutr Diet 2004;61:137-44.

11. NSW Government Action Plan for the Prevention of Obesity in Children and Young People 2003-7; NSW Government Response to the 2002 Obesity Summit. http://www.health.nsw.gov.au/obesity/adult/gap/index.html. Accessed 12 August 2004.

12. National Health and Medical Research Council. Acting on Australia's weight: A strategic plan for the prevention of overweight and obesity. Canberra: Australian Government Publishing Service; 1997. http://www.nhmrc.gov.au/publications/pdf/n22.pdf. Summary report accessed 12 August 2004.

13. Booth ML, Samdal O. Health-promoting schools in Australia: models and measurement. Aust N Z J Pub Health 1997;21(4 Spec No):365-70.

14. Swinburn B, Egger G, Fezeela R. Dissecting obesogenic environments: the development and application of a framework for identifying and prioritising environmental interventions for obesity. Prev Med 1999;29:563-70.

Louise A. Baur

The Children's Hospital at Westmead

Discipline of Paediatrics & Child Health, University of Sydney