The United States is falling behind its economic peers in most measures of health, despite making gains in the past two decades, according to a sweeping study of data from 34 countries.

Although Americans are living longer, with overall US life expectancy increasing to 78.2 in 2010 from 75.2 in 1990, increases in psychiatric disorders, substance abuse and conditions that cause back, muscle and joint pain mean many do not feel well enough to enjoy those added years of life.

"Despite a level of health expenditures that would have seemed unthinkable a generation ago, the health of the US population has improved only gradually and has fallen behind the pace of progress in many other wealthy nations," Dr Harvey Fineberg of the Institute of Medicine in Washington, DC, wrote in an editorial published on Wednesday with the study in the Journal of the American Medical Association (Jama).

The study by the Institute for Health Metrics and Evaluation at the University of Washington in Seattle is the first comprehensive analysis of disease burden in the United States in more than 15 years. It includes estimates for death and disability from 291 diseases, conditions, and injuries as well as 67 risk factors.

It is one of three new papers by the institute being released simultaneously at the request of first lady Michelle Obama, who plans to present the findings to mayors of US cities in an invitation-only event at the White House as part of her campaign to improve the nation's health.

They add to a growing pile of research showing that despite lavish spending on healthcare in the United States, Americans are failing to make significant gains in many measures of overall health.

In a 2010 report by the nonprofit Commonwealth Fund, the United States, despite spending twice as much on healthcare, came in dead last compared with six peers - Britain, Canada, Germany, Netherlands, Australia and New Zealand.

'MEDIOCRE' HEALTH

The latest study in Jama compared 20 years of health data from a vast number of surveys, published studies and death certificates in the United States with similar records in 34 high-income countries in Europe, Asia and North America.

Overall, the United States fell in the rankings between 1990 and 2010 on nearly every major health measure.

"Compared to other high-income countries, US health outcomes are pretty mediocre," said Dr Christopher Murray, director of the Institute for Health Metrics and Evaluation at the University of Washington, who led the study.

The researchers identified the leading causes of diseases, injuries and risk factors associated with disease over the past two decades. They found top causes of premature death in the United States still include heart disease, lung cancer and stroke, but suicide and road injuries also ranked among the leading causes of early deaths in the United States.

Among the leading diseases, the team found "a big and somewhat under recognised volume of disability in the US that is related to bone and joint disease - things like low back pain - as well as mental disorders and substance abuse," Murray said.

As for the top risk factors that lead to ill-health, a poor diet is the No. 1 cause, followed by tobacco, obesity and high blood pressure, he said.

Those may help explain why the United States consistently gets poor marks on these kinds of studies, Murray said.

KENTUCKY, GEORGIA, FLORIDA GETTING FIT

In addition to comparing the United States with other countries, the team also compared various counties within the US in a pair of studies focused on obesity and physical activity.

Those studies, published in the journal Population Health Metrics, found rising obesity rates in nearly all of the hundreds of US counties it studied between 2001 and 2009, but they also found that many Americans are becoming more physically active.

Counties in Kentucky, Georgia and Florida all reported major increases in the number of people getting sufficient physical activity, which the team defined as 150 total minutes of moderate activity or 75 minutes of vigorous activity per week.

For men, Concho County, Texas, proved to have the biggest increases in physical activity, with the ratio of men getting adequate exercise rising to 58.2 per cent in 2009 from 41.4 per cent in 2001.

For women, the biggest increase occurred in Morgan County, Kentucky, where the ratio of women getting adequate exercise rose to 44 per cent from 25.7 per cent.

"Understanding local trends in obesity and physical activity in both rural and urban areas will help communities develop successful strategies and learn from one another," said Dr Ali Mokdad of the University of Washington, who worked on both of the studies. - Reuters