A new study says high obesity rates caused disability rates to rise sharply in the last two decades among Americans younger than 60.

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The study by RAND Corp., which analyzed data from an annual nationwide survey of 36,000 households, is published in this month's edition of the journal Health Affairs.

Researchers found the number of people ages 30 to 49 who had problems caring for themselves or performing routine tasks increased by more than 50 percent from 1984 to 2000. It also found smaller but significant increases for people 18 to 29 and 50 to 59.

But disability rates declined by more than 10 percent for people ages 60 to 69, the study found.

Researchers said increasing obesity is the only factor that would explain such a large jump in disability. They warned the disability increase could have severe consequences for the nation's future health costs.

"People who are disabled generally use a lot more medical services so in the long run this trend could add a lot of costs to the nation's health care bill," researcher Dana Goldman said.

Musculoskeletal problems, such as chronic back pain, are linked to obesity -- and are one of the nation's leading causes of disability, along with mental illness. Obesity also is a major factor in the development of diabetes, which accounts for a small number of disability claims.

Additional Resources:

• RAND Corp.
• Health Affairs