Last week, Professor Boyd Swinburn, from Deakin University, and Jane Martin, Senior Policy Advisor for the Obesity Policy Coalition, wrote an article for the Crikey bulletin that critiqued the Productivity Commission’s recent report on childhood obesity.
Today, in another Crikey article, health policy analyst Jennifer Doggett has critiqued the critique.
Both articles follow below, for those Croakey readers who may have missed them in Crikey.
Why the Preventive Health Agency should ignore the Productivity Commission’s report on obesity
Professor Boyd Swinburn and Jane Martin write:
The Preventive Health Agency Bill, passed by the lower house last night (actually, Wed 27 Oct), is an important element in a comprehensive approach to addressing overweight and obesity.
The Agency will engage with a range of experts and take an evidence-based approach, a strategy also used by the expert group appointed by government – the National Preventative Health Taskforce – in developing their obesity prevention blueprint.
This is in stark contrast to Childhood Obesity: An Economic Perspective, a working paper produced by the Productivity Commission.
While the report is creating big headlines, it takes only a narrow economic assessment of the rationale for action on childhood obesity and an incomplete review of the evidence, concluding that major action is not warranted at this stage.
The Productivity Commission’s findings are at odds with those of the Taskforce. The findings are also inconsistent with two major Assessing Cost-Effectiveness (ACE) Studies, ACE Obesity and ACE Prevention, which identified a number of cost-effective interventions for obesity prevention.
For example, the ACE studies found that bans on junk food marketing to children and a 10% tax on junk food would have a high health impact while being cost saving, but the Productivity Commission’s report assessed their likelihood of success as low.
Three long-term, community interventions – Be Active Eat Well (primary schools), Romp and Chomp (pre-schools) and It’s Your Move (secondary schools) – have all been successful in reducing unhealthy weight gain in children in these settings and are ready to be translated to much larger scales.
Many other programs cited in the Productivity Commission’s report have also had positive results on behaviours and environments and, while none can be expected to provide the magic bullet, a combination of the most promising of these programs could be expected to make a significant difference to rates of overweight and obesity in children and young people.
This is the comprehensive approach recommended by the Taskforce, which hopefully will be implemented utilising the funding of around $400m for the Healthy Children and Healthy Communities initiatives through the Council of Australian Governments.
There are some telling gaps in the Productivity Commission’s assessment of the evidence. For example, almost all of the major evidence is missing from the report’s summary of research on unhealthy food marketing to children.
Specifically, there is no mention of the three leading international reviews of the evidence on the influence of junk food marketing on children, prepared on behalf of the World Health Organization and the US Institute of Medicine. These reviews have all reached clear conclusions: junk food advertising affects what children eat, what they want to eat and what they pester their parents to buy.
Professor Rob Moodie, Chair of the National Preventative Health Taskforce, led a previous analysis concluding that childhood obesity was a clear sign of ‘market failure’ because two key assumptions of the orthodox economic theory of markets are clearly violated: individuals do not consistently act in ways to maximise benefits to themselves because short term pleasures often trump long-term benefits; and children are very vulnerable to the commercial pressures which seek to manipulate them.
In contrast, the Productivity Commission, while conceding that children have very limited rationality and willpower in relation food choices, concluded that there were few ‘market failures’ in relation to childhood obesity, thus only weak, low risk strategies such as more education were justified. It appears that the general public understands the seriousness of childhood obesity and the vulnerability of children to commercial influences, as over 90% of consumers support bans on junk food marketing to children.
The Productivity Commission report states that childhood obesity’s causes and solutions are too complex to be certain, thus regulatory or fiscal strategies, despite evidence of their cost effectiveness, are not warranted and only the softer options of education and information should be used.
This approach is contrary to the widely held views of Australian and international experts in obesity, who agree that information and education alone will do nothing to address the childhood obesity problem. This approach will merely ensure that obesity in children, adolescents and adults continues to rise and that the obesity-driven tsunami of diabetes, cancer and other debilitating health consequences will continue unabated.
Despite the Productivity Commission’s assessment of the increasing health cost of this burden as a ‘probably minor’ externality, it is clear that its impact in the future will be serious. In addition to the financial burdens of spiraling health care costs and lost productivity, increasing numbers of obese children will continue to face serious health and psychosocial consequences in childhood, and disease and early death as adults.
Federal and State governments acknowledge that prevention is better than cure, and they must not let the Productivity Commission’s report deter them from putting this into action.
Claims about the benefits of banning junk food advertising to kids should be taken with a large pinch of salt
Health policy consultant Jennifer Doggett writes:
Claims by Professor Boyd Swinburn that the Productivity Commission (PC) got it wrong on childhood obesity should be taken with a pinch of (artery-hardening) salt.
The PC report, Childhood Obesity: An Economic Perspective, argues that there is little evidence for the cost-effectiveness of banning junk food advertising to children.
It is correct that both the WHO and ACE reports support Professor Swinburn’s position on junk food advertising. This is not surprising given that he played a key role in their production, acting as an advisor to WHO, providing background papers for the report, and sitting on both the Working Group and Obesity Research Team for the ACE report.
The Report from the Institute of Medicine did not conclude that junk food ad bans were cost effective but simply that there was good evidence that food advertising affects the beliefs about food and food choices of young children.
The evidence cited in the ACE-Prevention and WHO reports is based on research conducted by Professor Swinburn (among others) into the cost-effectiveness of junk food advertising bans. This research cites as its main source of evidence, a single randomised controlled trial on the impact of junk food advertising on children’s food choices.
Anyone bothering to look more closely at this study (and few journalists have the time or inclination to do this) would find that it was undertaken over 30 years ago in Canada. The study involved 288 children aged 5-8 from low income backgrounds attending a Summer Camp for two weeks in Quebec in the late 1970s (the paper was published in 1982). During the camp, the children were divided into four groups, with one group exposed to junk food advertising. The food choices of all children were monitored during the two week period of the camp and it was found that the children who had not seen the food advertising made healthier food choices than those who had.
Almost all current research making claims about the cost-effectiveness of junk food advertising bans relies, at some point, on the findings of this research. For example, Professor Swinburn’s model bases assumptions about how an advertising ban in Australia today would affect the food choices of children, over the course of their lifetime, on this study. The model discounts the effects of this intervention in Australia by a seemingly random 50% to account for the impact of the Internet and associated marketing changes on children today.
It hardly needs to be pointed out that a single, short-term, study, undertaken a generation ago, on a small group of children on the other side of the world, from a different social and cultural background, in a pre-Internet media environment, is hardly a robust evidence base for major public policy changes in Australia today. Changing any of the assumptions about the relevance of this study to contemporary Australian society (for example, altering projections of how changes in the food choices of children over a two week period would be sustained over their lifetime) would deliver significantly different results.
Despite the quasi-scientific gloss of academic studies in this area and their misleadingly precise findings (a junk food ad ban has a ‘gross incremental cost-effectiveness ratio of AUD$ 3.70 per Disability Adjusted Life Year’), their conclusions are only as robust as their assumptions. When put under the microscope, it is clear that these assumptions are based as much on conjecture, option and ideology as they are on science.
The PC was right to conclude that the cost-effectiveness of junk food ad bans has not been established.
If the Preventive Health Agency is genuinely committed to evidence-based policy it will take advice from the PC and allocate resources into interventions which have a better chance of success in reducing childhood obesity.
Update on 3 Nov. Adding a further comment from Boyd Swinburn:
I agree with Jennifer Doggett that policy must be as evidence-based as possible. However, randomised controlled trials of the effects of bans on junk food marketing to children on their junk food consumption or their unhealthy weight gain will never be done – just as they were never done for bans on tobacco advertising on smoking.
Thus the evidence to be used must be the best available rather than the best possible and this is particularly the case for modelling the cost-effectiveness of interventions. If anyone has any better evidence to place in the models we used with their highly transparent assumptions we would welcome it – that is the beauty of the models. However, having done many sensitivity analyses on the models, I can say that there are no plausible numbers that can be put into the models that would make the intervention cost-ineffective.
There is much direct evidence of the effect of food marketing on children’s food preferences and requests as any of the systematic reviews (that I was not involved with) demonstrate. There is much parallel evidence of the effects of marketing and marketing bans on the purchases of other goods.
There is enormous indirect evidence of the effects of junk food marketing on junk food sales – the food industry continues to invest in such practices based on the empirical data they have on their own sales in response to promotions. These people are not stupid. They invest hundreds of millions of marketing dollars a year targeting children because they produce results.
One must look at the totality of the evidence rather dive in to nitpick over one small section of it. It is a concern if public health people buy into the notion, now being heavily pushed by the industry, that all public health measures must have RCT-level empirical evidence of proof of effect before being enacted – that is not the meaning of evidence-informed public policy.
While I am happy to argue on the details of the evidence, Jennifer Doggett is correct that I also carry a view that marketing obesogenic food to children in the face of a childhood obesity epidemic is actually unethical and that society has a responsibility to protect children from commercial exploitation.
I suspect that the over 90% of the public who, in many opinion polls, support tougher regulations to restrict junk food marketing to children care less about the finer details of one corner of the pile of evidence on junk food marketing than they do about the straight ethics of the matter.