Letters

Childhood obesity

Breast feeding is important

Aim should be weight maintenance, not loss

Opportunity for physical activity has been lost

Healthy schools approach is needed

Interventions should be critically evaluated

Author's reply

Breast feeding is important

EDITORFrühbeck does not consider the role of infant feeding in the aetiology of childhood overweight and obesity.¹ Dewey et al found that formula fed infants were heavier than those who received no milk other than breast milk in the first 12 months, although they were of similar length and head circumference.² The study also found that the energy intake of breastfed infants was lower than that of formula fed infants, even after the introduction of solids, and suggested that relatively low energy intakes are a function of self regulation in breastfed infants.

Von Kries et al found in children aged 5 and 6 years a substantial, dose dependent, protective effect of breast feeding on obesity and overweight: three to five months of exclusive breast feeding was associated with a 35% reduction in obesity at the age of 5 to 6 years. They discuss the evidence for a programming effect of breast feeding in preventing obesity and overweight in later life.³ Breast feeding mothers lose weight after pregnancy more effectively than those who feed artificially, an advantage seen over at least the first 12 months of breast feeding.⁴ It seems that promoting and supporting breast feeding should be part of the initiative to tackle the "epidemic of obesity."⁵

Carol Campbell, clinical medical officer. 
Community Paediatric Department, Foyle Health and Social Services Trust, Londonderry BT47 1TG ccampbell{at}btinternet.com

Aim should be weight maintenance, not loss

EDITORFrühbeck's call for action over childhood obesity was heartening.¹ However, we have concerns about the focus of the editorial.

Firstly, we believe that weight maintenance rather than weight loss should be the goal of treatment of obesity in childhood while height growth continues. Weight loss is difficult to achieve, and drop-out rates are up to 90% in large series.² Additionally, ill-advised intake restriction may compromise nutrition and growth during vulnerable periods. Weight maintenance during the growing years is more easily achieved than weight loss³ and results in a gradual loss of overweight as height growth occurs. Weight maintenance is achieved by developing a stable energy balance and may therefore be more likely to result in long term maintenance of a healthy weight.

Secondly, the author failed to recognise the need for different approaches to the treatment of obesity in early childhood, late childhood, and adolescence, particularly in regard to the role of the family. A family centred approach is essential in early childhood as parents rather than children are responsible for the child's intake and energy expenditure. In later childhood and adolescence, individual work is needed with the young person but within the context of family involvement. ^{4 5}

We agree that there is no room for complacency over childhood obesity. However, the results of existing treatment programmes are generally disappointing, given the expense of multidisciplinary involvement. Much further work is needed to develop effective treatment programmes that can be undertaken by community health professionals. Early intervention by programmes that emphasise weight maintenance while height growth continues in childhood and early adolescence may offer the best and most cost effective way of preventing the morbidity associated with adult obesity.

Russell Viner, honorary senior lecturer in adolescent medicine. 
University College London Medical School, Middlesex Hospital, London W1N 8AA R.Viner{at}ich.ucl.ac.uk

Rachel Bryant-Waugh, consultant clinical psychologist. 
Great Ormond Street Hospital for Children, London WC1N 3JH

Dasha Nicholls, lecturer in behavioural sciences. 
Institute of Child Health, Great Ormond Street Hospital for Children

Deborah Christie, consultant clinical psychologist. 
Middlesex Adolescent Unit, Middlesex Hospital, London W1N 8AA

Opportunity for physical activity has been lost

EDITORI was surprised that Frühbeck failed to mention the societal factors that have had such a pivotal role in the development of childhood obesity.¹ The energy intake of preschool children has actually declined over the past 10 years,² but this has been outstripped by an increase in inactivity.³ Obesity has been created by structural changes that have reduced our nation's ability to make healthy choices. It is a political problem that demands political changes rather than behavioural or pharmacological interventions. We must create a less obesogenic environment for our children.⁴

As a child in the fifties I played in the street With hope in my heart and a ball at my feet My friends and I were out every day Life was just perfect child's play We cycled our bikes far and wide Into the welcoming countryside Climbing in trees, fishing in streams At night I had such sweet, sweet dreams Now in the Zeros my kids are denied Denied the childhood on which I thrived Streets filled with cars, cars everywhere Childhood destroyed, does anyone care? In the streets where once I stayed The cars are speeding In the streets where once I played Childhood now lies bleeding.

I am tired of reading articles bemoaning how our children spend all their time playing computer games and watching television. The sad reality is that most streets are now linear car parks with a central race track. It is too dangerous for children to play safely in their own streets. The Children's Play Council, Transport 2000, and Transform Scotland have been promoting a Dutch concept called home zones.⁵ These are streets that, with local community involvement, have been transformed into areas where children can play safely. Trees, picnic benches, and play equipment are placed in the street, and this physically prevents traffic from moving at more than 10 mph. Cars are guests, with pedestrians and cyclists having precedence. There are nine pilot schemes currently being monitored in England, and a few may soon begin in Scotland. Unfortunately, the funding is expected to come from already overstretched local authority transport budgets. Few home zones may ever be created. The relation between safe play and child health should be recognised centrally and ring fenced finance be provided to make all our neighbourhood roads into home zones.

Colin Guthrie, general practitioner. 
Glasgow G14 9DW grey_triker{at}hotmail.com

Healthy schools approach is needed

EDITORFrühbeck's editorial calls for action on childhood obesity.¹ In Liverpool, guidelines for schools on eating disorders and body image have recently been launched.² The guidelines are part of Liverpool's healthy schools award initiative.³ This is supported by the health authority and the city council and provides a coordinated approach to promoting health among school children. It forges links between education, health, parents, and the wider community to equip children and young people with the personal resources to empower them to pursue healthy lifestyles.

Frühbeck refers to the difficulty of maintaining, in the long term, classroom lessons on nutrition and physical health because of competition for school time.¹ The approach taken in the healthy schools award is for food and nutrition (and eight other areas) to be included across the curriculum and in the general ethos of the school not as an "add-on." In relation to food and nutrition one of the indicators of success is "to develop a cross-curricular approach to teaching about food and nutrition which enables pupils and staff to make positive connections between a balanced diet, safe hygiene practices, and health."

One hundred and fifty eight Liverpool schools are taking part in the initiative, and since 1997, 40 have achieved the award. The recent guidelines provide information about eating disorders and how schools can establish an environment which encourages a positive body image to counter some of the societal pressures that may contribute to eating problems.² Schools are encouraged to promote exercise and eating a healthy balanced diet as the most effective way to lose weight and maintain weight loss.

The healthy schools approach is being promoted nationally by the government in recognition that the school is a key setting in which to improve both health and education.⁴ Liverpool healthy schools programme is currently undergoing national accreditation following the launch of the national healthy schools scheme last year. The scheme provides national accreditation for education and health partnerships, and aims to ensure that evidence is gathered to demonstrate effectiveness. The standards that local healthy schools programmes must achieve for accreditation include taking a whole school approach to healthy eating and physical activity.⁴

The healthy schools approach is therefore an important means of acting to prevent and reduce childhood obesity and in time should provide evidence about the effectiveness of interventions.

Joyce Carter, consultant in public health medicine. 
Liverpool Health Authority, Liverpool L3 6AL joyce.carter{at}liverpool-ha.nwest.nhs.uk

Annette Lyons, senior effectiveness officer, personal social and health education. 
City of Liverpool Education and Lifelong Learning Service, Liverpool L1 4NX

1.	Frühbeck G. Childhood obesity: time for action, not complacency. BMJ 2000; 320: 328-329. (5 February.)
2.	Butler K. Guidelines for schools on eating disorders and body image. Liverpool: City of Liverpool Education and Lifelong Learning Service, 2000.
3.	City of Liverpool Education and Lifelong Learning Service. Liverpool healthy schools award manual. Liverpool: CLELLS, 2000.
4.	Healthy Schools. National healthy school standardguidance. Nottingham: Department for Education and Employment, 1999.

Interventions should be critically evaluated

EDITORFrühbeck states that "English and Scottish children showed a roughly twofold increase in weight for height in all age groups and both sexes."¹ The study she cited, however, showed that Scottish, not English, children increased their weight. Based on a similar statement on the prevalence of overweight another editorial proposed: "to alter this trend, strategies and programs for weight maintenance as well as weight reduction must become a higher public health priority."² Many other articles use similar logic: the prevalence of obesity and obesity related disease emphasises the need for concerted efforts to prevent and treat obesity.

What is disturbing in this logic is that the strategic plan starts right from action rather than considering the evidence of effectiveness. Numerous trials of interventions have taken place, varying from exercise to drugs and surgery to interventions in schools. But these are "necessity driven" actions rather then evidence driven. Before children are denied access to television, games, and chocolates, let us look at the evidence. Although some interventions promise limited effectiveness in weight reduction, not one trial has shown prevention of weight gain in the population. Not one trial has shown gains in clinically important end points (mortality and morbidity) after weight reduction or obesity prevention interventions. US guidelines on obesity in adults, prepared with the participation of the Cochrane Collaboration, did not cite any study supporting the efficiency of interventions.

Perhaps absence of evidence is the main reason why "less than half of obese adults report being advised to lose weight by health care professionals."³ The rate of physician counselling about exercise is low.⁴ Perhaps this is because physicians do not want to act without evidence. I believe that physicians must not be pressed to advise patients to buy weight reducing devices, etc, before they have the evidence that treating or preventing obesity is worth while.

We must rethink the history of obesity research. It is strange that despite criticism of the methodology of the Metropolitan Life Insurance Company study, which showed reduced mortality in obese people who had reduced their body mass, no other study has addressed this important question in over 50 years.

Vasiliy Vlassov, professor. 
Saratov Medical University, Saratov, 410601 Russia vvvla{at}sgu.ru

Author's reply

EDITOREditorials are constrained by lack of space and are not intended to be a wide ranging review but to highlight, as succinctly as possible, the basics of knowledge to date. Obesity has reached epidemic proportions. Thus, the epidemiological triad of host, agent, and environment can be used to consider causal factors. Features of the host affect obesity in ways that are not well understood. Some people seem more susceptible than others to weight gain. Campbell rightly points out the important role of breast feeding in preventing obesity in later life. Undoubtedly, factors that signal and regulate postnatal growth contribute to development of diseases in adulthood. In utero programming as well as nutritional programming during fetal life may result in permanent modifications of the neuroendocrine responses that are carried forward into adulthood.

In this epidemiological triad the agent is energy imbalance, where energy intake exceeds energy expenditure. The main modifiable factors affecting energy balance are dietary energy intake and energy expended through physical activity. I agree with Viner and colleagues that different approaches are needed to treat obesity in early childhood, late childhood, and adolescence. However, I do not share their view that weight maintenance rather than weight loss should be the goal. Merely concentrating on weight maintenance in overweight or obese children, hoping that they will grow out of the condition, has been shown to be ineffective and will not stem the escalating numbers of children entering medically defined categories of ill health.¹

The third entity is environment. This encompasses not just the physical environment, such as the layout of the cities, but economic and social organisation and cultural values. I agree with Guthrie that a less obesogenic environment for children has to be created. In this sense, the public health would benefit from going beyond a narrowly mechanistic focus on energy intake and physical activity and examining the economic, social, and cultural context more broadly. The best way to combat the problem is to help children avoid becoming overweight in the first place. The Liverpool healthy schools programme is welcome and represents the example to be followed. Clinical medicine and public health agencies have to act to prevent obesity with new partners, including food marketers and manufacturers, public and private healthcare purchasers, large employers, transportation agencies, urban planners, and real estate developers.

I admire Vlassov's diligence in scrutinising my references. To be precise, increases in all measurements (height, weight, and triceps skinfold thickness) except weight for height in English boys were found in the 1972, 1982, and 1990 surveys of the national study of health and growth. Data from the health survey for England 1996, a nationally representative sample of 2630 English children, showed that the frequency of overweight ranged from 22% at age 6 years to 31% at age 15 and that obesity ranged from 10% at 6 years to 17% at 15 years.¹ This reflects a rapid increase in overweight and obesity compared with previous UK surveys.

Despite Vlassov's claim, recommendations on obesity are evidence based. Vlassov is apparently not familiar with the systematic assessment and management approach based on evidence available from scientific studies and clinical trials, with primary care having a central role. The evidence report of the National Institutes of Health and the consultation convened by the World Health Organization are two excellent examples. ^{2 3} Vlassov is equally misguided about the absence of evidence regarding the benefits of treating or preventing obesity. Even modest reductions in weight of 5-10% of initial body weight are effective in decreasing associated comorbidity.⁴ Furthermore, a recently published prospective study of more than a million adults in the United States (457 785 men and 588 369 women) supported the well established increase in the risk of death from all causes, cardiovascular disease, cancer, or other diseases throughout the range of moderate and severe overweight for both men and women in all age groups.⁵

Gema Frühbeck, clinical scientist. 
Department of Endocrinology, Clinica Universitaria de Navarra, University of Navarra, 31008 Pamplona, Spain gfruhbeck{at}unav.es