Stagnation in the clinical, community and public ... - Wiley Online Library

clinical obesity

doi: 10.1111/j.1758-8111.2012.00052.x

Perspective

Stagnation in the clinical, community and public health domain of obesity: the need for probative research K. Casazza1 and D. B. Allison2

1

Department of Nutrition Sciences, University

of Alabama at Birmingham, Birmingham, AL, USA; 2School of Public Health, Office of Energetics, Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA

I think your solution is just. But why think? Why not try the experiment (Letter from John Hunter to Edward Jenner, 1795). In 1796, prompted by his mentor’s enjoinder, thought turned to action as Edward Jenner subjected his conjecture regarding smallpox resistance resulting from cowpox exposure to empirical testing. This hypothesis test revolutionized post-18th century medicine leading eventually to the smallpox vaccine. Indeed, higher order thinking links philosophy and science, but they are distinguished by the latter’s emphasis on systematic experimentation. In the context of obesity research, although we philosophize and debate the value and application of various public health messages as though the answers are ‘known’ for all intents and purposes, the strength of our progress has not matched the strength of our exhortations. We offer that one key factor limiting our success in identifying effective intervention and prevention strategies is the disproportionate effort spent on activities that serve to focus attention on popular conjectures as opposed to rigorously testing those conjectures with probative research. Hunter recognized that conjecture, regardless of how seemingly persuasive and reasonable, is still speculation until validated by experimentation. Our key point here is not that mainstream obesity researchers and activists mistake or misportray conjecture as proven fact (although this occurs also), but rather that even among many of those

who recognize the benefits of many popular proposals as conjectural, inordinate time, energy and money is spent on non-probative studies that seemed aimed at repeatedly calling attention to a proposition or generating emotion around the proposition rather than testing the proposition. As two commentators stated after an Institute of Medicine (IOM) Committee released a new set of recommendations and the National Institutes of Health (NIH), the Centers for Disease Control (CDC) and IOM released the documentary Weight of the Nation ‘. . . rather than evaluate the strategies’ effectiveness, they (the committee members) are just shouting them even louder’ (1) and ‘The nation’s most powerful anti-obesity groups are teaming up for a new HBO cable network documentary – but it pushes the same tired advice’ (1). Experimentation is conceptually simple, but often neglected. Although some public health advocates are dismissive of the plausibility and need for randomized experiments of public health recommendations and approaches, as discussed elsewhere, randomization, although sometimes challenging, is eminently doable in the public health domain (2). Suppose, for example, we propose that reducing access to or consumption of fast food will result in weight loss or less weight gain. On the surface, it seems like a reasonable claim and has been the basis for numerous public health policies and recommendations. But has the claim been verified? The answer is no. It would not be trivial to, for example, randomize a

© 2012 The Authors Clinical Obesity © 2012 International Association for the Study of Obesity. clinical obesity 2, 83–85

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large sample of persons to receive vouchers to fast food restaurants on the one hand vs. receive equivalent vouchers to a high-end grocery store (or other appropriate control) and guidance on avoiding fast food. Yet, it would surely be no less difficult than the randomized study of housing vouchers recently done (3), the randomized studies of obesity surgery that have been reported (4), the randomized study of a multicomponent ‘environmental intervention that included employee advisory committees, point-of-decision prompts, walking paths, cafeteria/ vending changes and educational materials’ in eight manufacturing companies (5), or the highly informative Diabetes Prevention Program (6). But such studies have not, to our knowledge, been done. Instead, as recently as 2012, we are provided with an analysis examining the association of pricing of fast food and its consumption (not even with weight data) (7), when a plethora of studies examining the association of fast food prices, availability, geographic proximity, consumption and obesity indices already exist (8–10). Surely, more association studies on this topic will not provide the definitive evidence that altering fast food price, availability or consumption will reduce obesity. Psychologists know the ‘mere exposure effect’, which states that the more we are exposed to something, the more we come to like it and are prepared to believe it. Is the thought that if we are simply repetitiously exposed to discussion of fast food and obesity with the commonly used vague words of ‘implicated’ and ‘linked’, we will come to believe the proposition has been proven? Is this why we have studies showing that fast food consumption is correlated with drug abuse (11), and depression (12,13), that it is inversely associated with educational achievement in children (14), that public support for regulations involving fast food have increased, that there are many pounds of saturated fat in a billion hamburgers (15), and that children rate food in fast food packaging more positively?(16) Although interesting, the aforementioned studies were published long after the conjecture that reducing fast food consumption will reduce obesity was advanced, so they were not needed to generate the conjecture. They draw attention, but do not test key hypotheses about the health benefits of actions. As another example, consider the ephedra debacle (17). A definitive study was never done to determine ephedra’s long-term weight and safety effects; rather, many millions of dollars were spent litigating by both the government and the private sector. Consequently, the Food and Drug Administration (FDA) (18) banned from the market a dietary supplement that may or may not have been safe, yet in randomized controlled trials was at least as effective as FDA-approved anti-obesity drugs (19,20). FDA did not do this by concluding that the risk of serious adverse effects had been scientifically demonstrated. Rather, the

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FDA concluded that uncertainty itself posed the risk, and that this risk was unreasonable given that the efficacy evidence was, in FDA’s view, insufficient. For a fraction of the costs spent litigating by industry and government, probative trials could have been conducted to provide unambiguous estimates of efficacy and certainly better, even if imperfect, estimates of risk in the scientific, not semantic sense. Careful consideration of what is and is not known is necessary to strengthen the scientific foundations of obesity recommendations. To do that, we must be honest with ourselves and our readers about what the evidence base actually shows, a practice that is sadly not uniform in the professional obesity literature (21). Then, we should use our resources – investigator time, taxpayer money, journal pages – wisely. Prior to investigators embarking on a study, editors publishing, and funders granting, they should ask ‘Does this (proposed) study really have the power to advance our knowledge about what works rather than merely raising attention or emotion?’ We do not mean to imply that there is no role for anything other than randomized efficacy and effectiveness studies with long-term obesity indices (weight, body mass index, adiposity) as outcomes, especially in the area of clinical obesity management. Non-randomized studies and studies of short-term effects on attitudes and behaviours such as purchasing, consumption, physical activity and so on can play vital roles in increasing understanding and in informing subsequent intervention design, yet we often seem to do such studies long after the period of their usefulness and at the expense of doing the probative studies that would answer key questions. Although experimental tests can be challenging, not all are unduly so. Many conjectures commonly advanced as recommendations to reduce weight gain or promote weight loss – ‘eat more meals with family members’, ‘reduce fast food availability’ ‘eliminate vending machines from schools,’ etc. – could be tested and we should challenge ourselves to do so more often in exchange for fewer additional studies of short-term endpoints, of surrogate outcomes, and of observational epidemiology serving primarily to raise attention. In the final analysis, John Hunter was right to question Jenner, and Jenner was right to test his hypothesis. This should be remembered by those undertaking obesity research.

Conflict of Interest Statement Dr. Allison has, anticipates or in the last 36 months has had financial interests with the Frontiers Foundation; Federal Trade Commission; Vivus, Inc.; Kraft Foods; University of Wisconsin; University of Arizona; Paul, Weiss, Wharton & Garrison LLP; Sage Publications. He has in prior years also had financial relationships with organizations with


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interests in fast food, ephedra, breakfast, fruits and vegetables, and vending machines. Dr. Casazza has nothing to disclose.

Acknowledgements We are grateful to Kyle Grimes for his suggestions on drafts of this paper. Written permission for inclusion has been obtained by Dr. Grimes.

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