WASHINGTON (AP) -- Older Americans in the most polluted parts of the country are significantly more likely to need medical treatment, particularly for lung ailments, according to a study that suggests reducing pollution could cut medical spending as well.

Earlier studies have established a link between air pollution and early death, but this is the first large-scale look at the impact on medical care itself, said Victor R. Fuchs, a Stanford University economist and lead author of the study being published Tuesday in the journal Health Affairs.

"With medical care spending exceeding $1 trillion per year, even a reduction of only a few percentage points would save society tens of billions of dollars annually," the study concluded. "Use of medical care is significantly higher in areas with more pollution."

The study found air pollution significantly increases Medicare recipients' medical care needs, even after controlling for region, population size, education, income, cigarette use and obesity. Because race plays such a large role in health, the study focused only on whites.

It examined 183 metropolitan areas with more than 100,000 people, using air pollution data from the Environmental Protection Agency, and averaged data from 1989-91.

Overall, it found air pollution was greatest in the West and lowest in Florida and Big Sky country. In general, it found hospital admissions were greatest in the Deep South and in southern states nearby: Arkansas, Oklahoma and Texas.

Specifically, the analysis found hospital admissions for respiratory problems were, on average, 19 percent higher in the 37 areas with the highest air pollution compared with the 37 areas with the least amount of pollution.

Similarly, outpatient care was 18 percent higher and hospital admissions were 10 percent higher.

Controlling for demographic and health factors, the researchers found Medicare would have saved an average of $76.70 per person in inpatient care and $100.30 in outpatient care for every drop of 10 micrograms per cubic meter in air pollution.

Economist Randall Lutter, a resident scholar at the conservative American Enterprise Institute, said it's already known that air pollution affects health. He criticized the study, saying it appeared to him to use very crude measurements to get at the differences around the country. He noted, for instance, that stress also can affect health, and stress may be very different in New York City than in Des Moines.

"You can't measure stress very well, and that's kind of a fundamental problem," he said. "It (the study) has some value, but it needs to be taken with a grain of salt."

Copyright 2002 The Associated Press. All rights reserved.