Obesity drives U.S. healthcare costs up by 29%, but amounts vary by state

The number of obese American adults continues to rise and so do the healthcare costs associated with treatment for illnesses related to the condition.

Indeed, new research finds that U.S. healthcare resources devoted to treating obesity-related illnesses in adults increased 29% from 2001 to 2015. But there are significant differences per state.

Obesity now affects more than 36% of U.S. adults, according to the latest data from the Centers for Disease Control and Prevention. And last year the agency found obesity was associated with increased risk of 13 types of cancer.

The study, published in Clinical Chemistry, analyzed data from the Medical Expenditure Panel Survey for 2001-2005 and estimated the percentage of healthcare costs that were associated with adult obesity, both for the U.S. as a whole and for the most populous states. Researchers also reviewed the literature on the impact of obesity on economic outcomes, such as medical care costs, employment and wages.

The research team found that in 2015, Arizona, California, Florida, New York and Pennsylvania devoted 5% to 6% of their total medical expenditures to treating obesity-related illness. But North Carolina, Ohio and Wisconsin spent more than twice that—more than 12% of all healthcare dollars in those states were used to treat obesity-related illness. The study also reports results by payer type, including private health insurance companies, Medicare and Medicaid.

"Once again, we find dramatic differences across states in the fraction of Medicaid spending that is devoted to obesity-related illness," study author John Cawley, professor of policy analysis and management at Cornell University, said in an announcement. "For example, over 2001-15, Kentucky and Wisconsin devoted over 20% of their Medicaid spending to obesity-related illness. In contrast, in New York, 10.9% of Medicaid spending was devoted to obesity-related illness, and the average for the U.S. as a whole was 8.23% during that period."

Cawley said the differences across states are driven by a number of factors, such as differences in obesity prevalence, healthcare access by obese individuals, how obesity is treated and prices of healthcare.

Researchers could not generate estimates for less populous states because of limited information about their residents in the data. Previous estimates of the healthcare costs of obesity by state were not based on microdata for each state, but on assumptions about how national costs should be apportioned to different states.