Most Medicare spending growth has been due to a rise in the number of seniors who are treated for multiple medical conditions, particularly obesity, a new study finds.

In 1987, 31% of beneficiaries received treatment for five or more medical conditions, according to a study in the journal Health Affairs. By 2002, the number of beneficiaries with five or more conditions made up 50% of the Medicare population. Also, while they accounted for about half of Medicare spending in 1987, by 2002, they took up three-fourths of total program spending.

Obesity played a prominent role in the spending growth. The level of obesity among beneficiaries doubled from 1987 to 2002. At the same time, Medicare spending on this group almost tripled, according to the study.

See the study at .