The study’s authors claim that the health care cost of obesity could be as high as $168bn a year – about 17 percent of total US medical care costs and significantly higher than the $147bn cited by the Institute of Medicine based on a previous study.
More than a third of the US population is now obese, and nearly the same proportion again is overweight, according to statistics from the Centers for Disease Control and Prevention. Obesity is known to increase risk of a range of health conditions, including type-2 diabetes, heart attack, stroke, certain cancers, hypertension, osteoarthritis, asthma and depression, among others.
The authors claim that although previous research has been valuable in demonstrating the significance of health care costs, underestimating those costs could lead to underinvestment in obesity prevention strategies or underestimates of those strategies’ cost-effectiveness.
“This paper makes an important contribution by providing the first estimates of the causal impact of obesity on medical care costs, which are significantly higher than the estimates of the association that are published in the previous literature, and thus have important implications for insurance, government policy, and estimates of the cost-effectiveness of anti-obesity interventions,” the authors wrote.
The researchers developed an instrumental variable technique to examine not only the correlation of obesity with health care costs, but to find evidence of the causal effect of obesity on health care costs. For example, causality could be overestimated if a person becomes obese after suffering chronic depression, and has higher medical costs due to the depression – or underestimated if an obese person has less access to medical care. Another limitation of previous studies has been the self-reporting of weight data, which many people are known to understate. The researchers’ method of statistical analysis was designed to minimize this effect.
Source: National Bureau of Economic Research
"The Medical Care Costs of Obesity: An Instrumental Variables Approach"
Authors: John Cawley and Chad Meyerhoefer