摘要：We investigated the appropriateness of basing childhood obesity interventions on expectations of return on investment (ROI). We show that excess weight is indeed associated with greater medical expenditures even among children and adolescents. However, under current best practices, it is unlikely that interventions will be able to meet the level of effectiveness required at a low enough implementation cost to show positive ROI. The merits of childhood obesity interventions should be based on their ability to efficiently control weight and improve health compared with alternative uses for available resources. They should not be based on the potential for short-term financial savings. THE WELL-DOCUMENTED RISE in the prevalence of obesity in the United States is not limited to adults. The prevalence of overweight in children, defined based on 2000 Centers for Disease Control and Prevention growth charts, has also increased dramatically. Between the 1960s and 2002, the prevalence of overweight among children and adolescents aged 6 through 19 years grew from roughly 4% to 16%, a 300% increase. 1 , 2 Because obesity increases the risk of a host of adverse medical conditions, there has been considerable attention paid to the economic consequences of the current obesity epidemic. Research has focused on quantifying excess medical expenditures paid by the federal and state governments. Finkelstein et al. showed that total medical expenditures would be roughly 9% lower if there were no obesity among adults and that nearly half of the annual $90 billion obesity price tag is financed by Medicare and Medicaid. 3 A follow-up report that quantified the costs of obesity among full-time employees found that because of increased medical expenditures and absenteeism, a 1000-person firm spends roughly $277000 more per year because of obesity. 4 These estimates provide an idea of the magnitude of the savings that could be achieved through successful reductions in obesity. The growing interest in quantifying the economic consequences of childhood overweight is driven by 2 considerations. The first, return on investment (ROI), focuses only on costs and compares the medical and other costs saved by the intervention with the cost of implementation. The logic is that if the costs of childhood overweight are high enough, the likelihood of funding interventions aimed at reducing them will increase. The second measure, cost-effectiveness, calculates the net change in costs associated with an intervention relative to the health benefits gained, usually measured as quality-adjusted life-years gained. Interventions that reduce excess weight in children can be cost-effective even if they do not show a positive ROI (i.e., even if there is no net cost saving). In fact, this is the case for most medical and surgical interventions; they improve health but also increase costs. Although there is no common threshold that signifies a cost-effective intervention, medical and surgical interventions that have a cost-effectiveness ratio below $50 000 per quality-adjusted life-year are often considered to be cost-effective. 5 There are 2 features of the market for obesity prevention and treatment that are relevant for analyzing the ROI of interventions. First, most of the costly complications of obesity do not appear until later in life. 6 Because many of the conditions that obesity contributes to rarely occur in children, it is possible that the costs of childhood overweight are small or nonexistent, at least in the short run. Two previous studies support this conclusion. 7 , 8 Second, the time horizon used when calculating ROI is crucial. There is evidence that overweight children are far more likely to become obese adults, 9 , 10 whose health risks and costs are substantially greater than those of normal-weight adults. Looked at from a lifetime perspective, which is the appropriate time frame for cost–benefit and cost-effectiveness analysis, interventions whose main impact is to reduce costs in the future can still show positive ROI. We review the business case for interventions aimed at reducing childhood overweight and discuss the appropriateness of basing interventions targeted at children on expectations of ROI. We report new estimates of the cross-sectional costs of childhood overweight. We then use these to answer the following question: how likely is it that a childhood overweight intervention will pay for itself through reductions in health care payments within 5 years? Five years is appropriate because it is rare for researchers to track cost and benefit data beyond this time period (partly because of the 5-year National Institutes of Health funding cycle) and because this is roughly the time period that employers consider when determining investments for employee (and dependent) wellness. We then discuss the implications of relaxing the 5-year target for ROI.
