IJE Advance Access originally published online on December 8, 2005
International Journal of Epidemiology 2006 35(1):79-80; doi:10.1093/ije/dyi261
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Commentary |
Commentary: Counterpoint to Campos et al.
Director of Policy and Public Affairs, IASO International Obesity Task Force, London, UK. E-mail: nrigby{at}iotf.org
It is unusual to find academics concerned chiefly with legal, social, political, and educational issues seeking to challenge the whole arena of the epidemiology, clinical, and public health aspects of the obesity problem. To start from scratch to deal with all their spurious statements in this response is hardly appropriate. The suggestion that there is growing ‘concern’ about the validity of the serious health issues associated with obesity is really quite bizarre, as there has been the most remarkable and growing consensus among an extensive range of governments, academics, health economists, and policy makers relating to the impact of excess weight gain. Here are a few simple facts.
Obesity as a disease: Many readers may be surprised to learn that obesity was first included in the International Classification of Diseases in 1948. Perhaps because of its relative rarity, obesity as a disease was not questioned at that time.
Uniform categories of body mass index (BMI) to identify overweight and obesity were first determined by a World Health Organization expert consultation convened in 1993.2 The growing global dimensions of the obesity epidemic, and the double burden of disease this imposes on countries undergoing nutrition transition, were then recognized by another WHO expert consultation, for which the International Obesity Task Force (IOTF), formed in 1996, provided comprehensive background reports from working groups involving scientists from many countries, including China, which even then recognized that overweight and obesity posed a significant health risk to its population.3
More recently a national nutrition survey in China estimated that the obesity rate almost doubled to 7.1%—or 60 million adults—between 1992 and 2002, with 22.8% of the population—200 million—now overweight. The adult overweight and obesity rates in urban areas reach 30.0 and 12.3% each and the childhood obesity rate has also grown to 8.1%. It is also significant that in China's megacities, the prevalence of diabetes among adults has increased from 4.6 to 6.4% in <10 years.4
The crude range of ‘normal’ BMI may not be the optimum for everybody, particularly if they come from developing countries, e.g. Asian populations, with central obesity and related metabolic disturbances found at lower BMIs.5 An IOTF expert working group examined data on BMI and risk factors for Asians, noting that people with a high proportion of body fat, irrespective of their BMI, were susceptible to the health risks associated with obesity.6 This led to a WHO review of the implications for Asian populations and a recommendation for a lower ‘action point’ of BMI > 23 for Asians.5
The next issue is about shifts in average weights and extreme weights. This is an elementary public health issue where only small increases in average BMI are associated with marked increases in the proportion of people with extremely high values. But it is widely acknowledged that the risk of illness increases with modest increases in weight, starting from a BMI of 
21.3,7 The progressive increase in risk has been demonstrated in many studies in the USA, Europe, and Asia including the Nurses Health Study, the Marks and Spencer Cardiovascular Risk Factor Study, and the Asia Pacific Cohort Studies Collaboration to mention but a few.8–10
Quoting single articles in an attempt to refute the importance of weight gain as a predictor of morbidity and premature mortality suggests a somewhat distorted view or a lack of understanding of how conclusions in this field are developed on the basis of many studies that are carefully scrutinized for their validity. The field of medical and scientific research has never been more unified in expressing its concern about the medical and personal disadvantages associated with excess weight gain as evidenced in a succession of WHO reports and other scientific statements, particularly those issued in the US, with broader acknowledgement of the pathways leading from obesity towards its manifold co-morbidities.11,12
The metabolic syndrome is now widely recognized as a complex of related risk factors emphasizing the importance of central obesity as a marker for very real medical consequences, particularly type 2 diabetes and cardiovascular disease; this was estimated to affect 64 million American adults in 2000—a 28% increase in a single decade.13
The doubts voiced by Campos et al. suggesting that the data do not support the claim of an epidemic of obesity seem to deny the obvious and emanate from a curiously narrow American perspective, spun in rhetoric more redolent of a courtroom contest than serious academic discourse.
The inconsistency of the argument involves both questioning reality (What if the so-called obesity epidemic is largely an illusion?) and a ‘so what’ approach—does it really matter? Adducing evidence to suggest ‘obesity may be an early symptom of diabetes rather than its underlying cause,’ the authors then invite us, before reaching a verdict, to consider in conclusion ‘what if’ higher than average weight may have no medical significance at all?
Is the significance of the public health importance of obesity diminished by the recent analysis of deaths based on revised Centers for Disease Control data? This concluded that obesity accounts for 112 000 deaths (range 54 000–170 000), far fewer than previous estimates.14 However, suggested flaws in this analysis were examined at a recent symposium at the Harvard School of Public Health where it was contended that a bias through not controlling for pre-existing chronic disease may have skewed the figures.15 Nevertheless, 112 000 obesity-related deaths remain significant.
However, the crux of the Campos case lies in a confusion between mortality and morbidity. The onset and duration of illness, the impaired quality of life and the economic costs (both personal and societal) are overlooked; the proposition that an association between overweight and obesity and the risk of developing a range of co-morbidities is well established is also questioned by Campos, who nevertheless suggests that fatness may be caused by a metabolic disease, rather than being a causal factor.
Oddly Campos seems to wish to avoid the idea that overweight and obesity could be the result of over-consumption, suggesting that the ‘majority’ of people (in the US) weigh only 3–5 kg more than they did a generation ago, gratuitously asserting that ‘the average American's weight gain can be explained by 10 extra calories a day,’ or a few minutes walking.
Is it credible to attribute the remarkable collective increase in BMI—such that American aviation authorities have had to review their standard passenger winter weight tables to allow for an ‘average’ 199 lb man (90 kg)—to no more than sipping the froth on a daily cappuccino?16
In fact the US government's Department of Agriculture provides a firmer foothold with evidence, deftly ignored in the diet vs activity debate, that the ‘average American’ consumes about 530 kcal per day more—almost a 25% increase in energy intake compared with 30 years ago.17
The impact on children is one aspect of the obesity epidemic that Campos does not dwell upon. The IOTF childhood and adolescent obesity working group reported to the WHO that 10% of the world's children were now overweight, with at least three times that level in the Americas.18 In the USA it has been estimated that 2 million overweight adolescents currently have a metabolic syndrome phenotype, a doubling over the past decade.19
The questioning by Campos of weight loss as a practical goal, which can improve health, is also bound up with the claim that public health measures to reduce obesity are ‘striving to achieve a presently unachievable goal of unknown medical efficacy’, a strange proposition from an author who confides in his well-publicized book that he was obese when he began writing, but lost 55 lbs in the 4 years he took to finish his manuscript.
Weight loss has been shown not only to improve measurable health outcomes, but also to improve psychological well-being as Campos attests in his book. Perhaps the most striking evidence of benefit was shown in the United States Diabetes Prevention Program that was ended a year ahead of schedule because the data were so convincing in showing major impact of ‘lifestyle’ improvements through increasing activity and reducing weight in preventing type 2 diabetes in individuals with impaired glucose tolerance.20
While he suggests that reducing bodyweight is a poor target for public health, he disregards public health efforts aimed at prevention of overweight and obesity, an essential target if the obesity epidemic is to be stemmed.
Where Campos perhaps strikes a note of valid concern is in considering the tenor of the mass media's adversarial coverage of the issue of obesity in the US—which he likens to a ‘moral panic’. Saturation coverage laying blame on individuals, with maverick commentators feeling free to disparage and stigmatize the obese, only throws up a smokescreen to conceal the underlying structural factors in a society where ubiquitous opportunities to consume to excess combined with minimal need for physical motion make obesity almost an inevitability for some, and where the disproportionate impact of obesity among disadvantaged groups also reflects the vast social inequalities in health.
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 Top References |
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1 Campos P, Saguy A, Ernsberger P, Olever E, Gaesser G. The epidemiology of overweight and obesity: public health crisis or moral panic? Int J Epidemiol 2006;35:55–60.
2 World Health Organization. Physical Status: the use and interpretation of anthropometry. WHO Technical Report Series 854. Geneva: WHO, 1995.
3 World Health Organization. Obesity: preventing and managing the global epidemic. WHO Technical Report Series 894. Geneva: WHO, 2000.
4 Statement by Wang Longde, Chinese vice minister of health, reported in People's Daily November 2004. Available at: http://english.people.com.cn/ (Accessed July 17, 2005).
5 WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies—WHO expert consultation. Lancet 2004;363:157–63.[CrossRef][ISI][Medline]
6 James WPT, Chunming C, Inoue S. Appropriate Asian body mass indices? Obes Rev 2002;3:139.[CrossRef][Medline]
7 James et al. Chapter 8: Overweight and obesity (high body mass index). In: Ezzati M, Lopez AD, Rodgers A, Murray CJL (eds). Comparative Quantification of Health Risks: Global and Regional Burden of Disease Attributable to Selected Major Risk Factors. Geneva: WHO, 2005.
8 Willett WC, Manson JE, Stampfer MJ et al. Weight, weight change, and coronary heart disease in women. Risk within the ‘normal’ weight range. JAMA 1995;273:461–65.[Abstract]
9 Ashton WD, Nanchahal K, Wood DA. Body mass index and metabolic risk factors for coronary heart disease in women. Eur Heart J 2001; 22:46–55.
10 Asia Pacific Cohort Studies Collaboration. Body mass index and cardiovascular disease in the Asia-Pacific Region: an overview of 33 cohorts involving 310 000 participants. Int J Epidemiol 2004;33:751–58.
11 Grundy SM, Pasternak R, Greenland P, Smith S Jr, Fuster V. AHA/ACC Scientific Statement: Assessment of cardiovascular risk by use of multiple-risk-factor assessment equation. J Am Coll Cardiol 1999; 34:1348–59.
12 Eyre H, Kahn R, Robertson RM et al. Preventing cancer, cardiovascular disease, and diabetes: a common agenda for the American Cancer Society, the American Diabetes Association, and the American Heart Association. Circulation 2004;109:3244–55.
13 Ford ES, Giles WH, Mokdad AH. Increasing prevalence of the metabolic syndrome among U.S. Adults. Diabetes Care 2004;27:2444–49.
14 Flegal KM, Graubard BI, Williamson DF, et al. Excess deaths associated with underweight, overweight, and obesity. JAMA 2005; 293:1861–67.
15 Weighing the Evidence: Symposium on Overweight, Obesity and Mortality Harvard School of Public Health May 26 2005.
16 US Department of Transportation Federal Aviation Circular AC 120-27D 8/11/04.
17 US Department of Agriculture Factbook 2001–2002.
18 Lobstein T, Baur L, Uauy R. IASO International Obesity TaskForce. Obesity in children and young people: a crisis in public health. Obes Rev 2004;5 (Suppl. 1):4–104.
19 Duncan GE, Li SM, Zhou XH. Prevalence and trends of a metabolic syndrome phenotype among U.S. adolescents, 1999–2000. Diabetes Care 2004;27:2438–43.
20 Diabetes Prevention Program Research Group. Reduction in the Incidence of Type 2 Diabetes with Lifestyle Intervention or Metformin. N Engl J Med 2002;346:393–403.
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