WASHINGTON (Reuters) - Americans die sooner than citizens of a dozen other developed nations and the usual suspects -- obesity, traffic accidents and a high murder rate -- are not to blame, researchers reported on Thursday.

Devices used to take blood pressure, temperature, and examine eyes and ears rest on a wall inside of a doctor's office in New York March 22, 2010. REUTERS/Lucas Jackson

Instead, poor healthcare may be to blame, the team at Columbia University in New York reported.

They found that 15-year survival rates for men and women aged 45 to 65 have fallen in the United States relative to the other 12 countries over the past 30 years.

Such figures are frequently cited by supporters of healthcare reform, and critics often point out that the United States also has higher rates of obesity, more traffic fatalities and more murders than these countries.

Columbia’s Peter Muennig, who led the study published in the journal Health Affairs, said his team accounted for these factors this time.

“But what really surprised us was that all of the usual suspects -- smoking, obesity, traffic accidents, and homicides -- are not the culprits,” Meunnig said in a statement.

“The U.S. doesn’t stand out as doing any worse in these areas than any of the other countries we studied, leading us to believe that failings in the U.S. health care system, such as costly specialized and fragmented care, are likely playing a large role in this relatively poor performance on improvements in life expectancy.”

In June, the Commonwealth Fund, which advocates on and does research focusing on healthcare reform, reported that Americans spend twice as much on healthcare as residents of other developed countries -- $7,290 per person -- but get lower quality and less efficiency.

Muennig and Sherry Glied compared the United States to Australia, Austria, Belgium, Britain, Canada, France, Germany, Italy, Japan, the Netherlands, Sweden and Switzerland.

All these countries provide universal health insurance, in contrast to the United States, where 15 percent of the population lacks health insurance, although healthcare reform passed in March is designed to lower that disparity.

Republicans have promised to derail the legislation if they gain power in Congress in next month’s elections.

COSTS GO UP

Between 1975 and 2005, medical costs went up in all the countries, as did life expectancy.

But costs went up far more in the United States and life expectancy increased to a far lower degree.

Glied and Meunnig do not believe obesity accounts for the differences. While more Americans are obese, overall the populations in all the nations have been getting fatter, they said.

“For obesity to explain the decline in U.S. life expectancy or the increase in health spending relative to the 12 comparison countries, Americans would have to be becoming obese at a faster rate than people in the comparison nations over time,” they wrote. But this has not been happening.

Americans are less likely to smoke, and while Americans are more likely to die in car crashes or be murdered, again these rates do not explain the lower life expectancy, the Columbia team said.

“The findings undercut critics who might argue that the U.S. health care system is not in need of major changes,” they wrote.

They noted that the United States has been dropping in life expectancy tables for decades.

“In 1950, the United States was fifth among the leading industrialized nations with respect to female life expectancy at birth, surpassed only by Sweden, Norway, Australia, and the Netherlands,” they wrote. At last count, the United States was 46th in female life expectancy; 49th for both sexes.