October 30 (HealthDay News) -- In 2007, six major illnesses among Americans age 65 and older resulted in medical and lost productivity costs of more than $196 billion, according to researchers who analyzed Medicare and National Health Interview Survey data.

The six major illnesses examined in the study were: chronic lung disease, ischemic heart disease, stroke, lung cancer, pneumonia and gastrointestinal illness. The total cost of the six conditions in 2000 was almost $135 billion. The researchers factored in population growth and increases in medical care costs since then to arrive at the 2007 figure.

In 2000, ischemic heart disease was the most expensive of the six diseases, costing $60 billion. The least expensive was gastrointestinal illness at $500 million.

"As our population continues to age, we expect that the total cost burden of these illnesses will also continue to increase," study lead author George Van Houtven, senior economist at RTI International, said in a news release from the research institute. "To reduce these costs, we need to give priority to prevention strategies including environmental quality improvements."

The study was published in RTI Press.

SOURCE: RTI International, news release, Oct. 22, 2008