Obesity Epidemiology

13Economic Costs of ObesityGraham A. Colditz and Y. Claire WangIntroductionAs the prevalence of overweight and obesity continues to climb, the challenges of quantifyingthe impact of this epidemic to inform public policies and health services become morepressing. The consequences of obesity on population health are far- reaching—asextensively discussed in Chapters 8 to 12: the society bears its burden from prematuremortality, morbidity associated with numerous chronic conditions, and negative impactson health-related quality of life. One useful metric to summarize the overall burden fromsuch broad impact on the health care system and the society at large is the economic costsof obesity. Such metric can encompass the financial consequences of medical resourcesdevoted to treating all obesity-related fatal and nonfatal conditions, productivity loss, andthe psychosocial burden from suffering and poorer quality of life, forgone job opportunities,and other disruptions in life plans. Laying out the economic consequences of obesityin monetary terms tells us how much the population is paying for obesity-related costs(expenditure or opportunity costs). Subsequently it identifies the components of such burdenand the share of these costs borne by each sector in the society. It is argued that such informationcan highlight research and funding priorities and help build political will to addressthe obesity epidemic.In the 2001 U.S. Surgeon General’s call to action to prevent and decrease overweightand obesity, the costs of obesity to the United States were cited to be $117 billion in2000 1 —a figure likely much greater today. This estimate includes $61 billion in directcosts (costs incurred in the health care process) and $56 billion in indirect costs(forgone wages and productivity). 1,2 Details on these two components of economic costsof obesity as well as some less tangible aspects of obesity’s burden will be providedin the section “Components of Economic Burden of Obesity.” Methods adopted in thestudies aimed to estimate costs of obesity can generally be classified to two types: theprevalence- and incidence-based approaches. The prevalence-based approach is the mostcommon; it estimates the total costs incurred in a given year attributable to obesity. Theincidence-based approach, on the other hand, often involves calculating the lifetime costs.The section “Methods of Quantifying Economic Cost” surveys the literature to describethese two approaches and discusses the strengths and weaknesses of each method. Thesection “Who Bears the Economic Costs of Obesity?” reviews studies for insights onwho shoulders the overall cost burden of obesity. Finally, the section “Knowledge Gapand Future Research” addresses criticisms and limitations of the cost-of-illness estimatesand discusses key knowledge gaps and future research directions.261