WEDNESDAY, Aug. 24 (HealthDay News) -- Obesity is costing states up to $15 billion each year, a new study suggests.

In nine states, obesity already accounts for 10 percent or more of the state's annual medical expenses, according to researchers from RTI International, Duke University and the U.S. Agency for Healthcare Research and Quality.

The study pointed out that taxpayers are footing a large part of the bill, with the state's share of obesity expenditures funded by Medicare and Medicaid ranging between 25 percent in Virginia and a whopping 64 percent in Rhode Island.

"This study shows that the toll that obesity takes goes beyond impairing the health of individuals to imposing a major burden on the entire health care system," AHRQ Director Dr. Carolyn M. Clancy said in a news release. "Reducing the prevalence of obesity and its complications is an important priority for the nation and requires focused and constant attention."

An update of 2004 state-by-state estimates, the study revealed that as of 2009, California has the highest estimated total obesity-related costs of $15.2 billion at the state levels and obesity-related Medicare expenditures of $3.4 billion. Meanwhile, New York has the highest estimated obesity-related Medicaid expenses a year: $4 billion.

Across the board, the study found that Wyoming has the lowest estimated costs attributed to obesity, with total state-level expenses of $203 million.

The study also noted the total annual medical estimates related to obesity are 10 percent or higher in Alabama, Alaska, Indiana, Louisiana, Michigan, Mississippi, Ohio, South Carolina and Tennessee.

In comparison, the researchers found, Colorado and Hawaii have the lowest percentage of annual obesity-related medical estimates, at roughly 7 percent each.

The study authors concluded that obesity accounts for a significant -- and preventable -- portion of the nation's medical bill.

"This evidence clearly indicates that obesity imposes high annual total and public sector medical costs on state budgets," study author and RTI health economist Justin Trogdon said in a news release. "The high costs emphasize the need to prevent and control obesity as a way to manage those costs."

More information

The U.S. Centers for Disease Control and Prevention provides more information on obesity.