RESEARCH TRIANGLE PARK, N.C. – The expanding waistlines in America are costing the economy as much as $147 billion a year in 2008 compared to $78.5 billion in 1998, according to researchers and two other organizations.

Data from 1998 through 2006 shows that obesity in the U.S. increased by 37 percent, driving up related costs to 9.1 percent of medical expenditures, the researchers said. is available at the Health Affairs web site.

“In 1998 the medical costs of obesity were estimated to be as high as $78.5 billion, with roughly half financed by Medicare and Medicaid,” an abstract of the study says. “This analysis presents updated estimates of the costs of obesity for the United States across payers (Medicare, Medicaid, and private insurers), in separate categories for inpatient, non-inpatient, and prescription drug spending.

“We found that the increased prevalence of obesity is responsible for almost $40 billion of increased medical spending through 2006, including $7 billion in Medicare prescription drug costs. We estimate that the medical costs of obesity could have risen to $147 billion per year by 2008.”

Obesity-related health costs were 6.5 percent of the national total in 1998.

An obese person incurs on average $1,429 per year, or 42 percent, more in medical costs, the study found.

Obesity is responsible for 8.5 percent of Medicare procedures, 11.8 percent of Medicate costs and 12.9 percent of private healthcare costs.

Researchers from the Agency for Healthcare Research and Quality, and the U.S. Centers for Disease Control & Prevention were also involved in the project.

"Although bariatric surgery and other treatments for obesity are increasing in popularity, in actuality these treatments remain rare," said Eric Finkelstein, director of RTI’s Public Health Economics Program who was the study’s lead author. "As a result, the medical costs attributable to obesity are almost entirely a result of costs generated from treating the diseases that obesity promotes. Thus, obesity will continue to impose a significant burden on the health care system as long as the prevalence of obesity remains high.”

The CDC Foundation funded the study.