WASHINGTON — The United States suffers far more violent deaths than any other wealthy nation, due in part to the widespread possession of firearms and the practice of storing them at home in a place that is often unlocked, according to a report released Wednesday by two of the nation’s leading health research institutions.

Gun violence is just one of many factors contributing to lower U.S. life expectancy, but the finding took on urgency because the report comes less than a month after the shooting deaths of 26 people at an elementary school in Newtown, Conn.

The United States has about six violent deaths per 100,000 residents. None of the 16 other countries included in the review came anywhere close to that ratio. Finland was closest to the U.S. ranking with slightly more than two violent deaths per 100,000 residents.

For many years, Americans have been dying at younger ages that people in almost all other wealthy countries. In addition to the impact of gun violence, Americans consume the most calories among peer countries and get involved in more accidents that involve alcohol. The U.S. also suffers higher rates of drug-related deaths, infant mortality and AIDS.

The result is that the life expectancy for men in the United States ranked the lowest among the 17 countries reviewed, at 75.6 years, while the life expectancy for U.S. women ranked second lowest at 80.7 years. The countries reviewed included Canada, Japan, Australia and much of Western Europe.

The U.S. has long lagged in life expectancy compared with other economically developed nations. In this study, researchers culled existing studies to examine why. Most statistics in the report are from the late 1990s through 2008. The report found that U.S. health disadvantages aren’t limited to the poor and uninsured. Even white, college-educated, and wealthier Americans tend to be in worse health than their peers in other developed countries.

The nation’s health disadvantages have economic consequences. They lead to higher costs for consumers and taxpayers as well as a workforce that remains less healthy than that of other high-income countries.

“With lives and dollars at stake, the United States cannot afford to ignore this problem,” said the report from the National Research Council and the Institute of Medicine.

In attempting to explain why Americans are so unhealthy, the researchers looked at three categories: the nation’s health care system, harmful behaviors and social and economic conditions. Researchers noted that the U.S. has a large uninsured population compared to other countries with comparable economies, and more limited access to primary care. And although the income of Americans is higher on average than that of other wealthy countries, the United States also has a higher level of poverty, especially among children.

Researchers said American culture probably plays an important role in the life expectancy rates falling short of other wealthy countries.

“We have a culture in our country that, among many Americans, cherishes personal autonomy and wants to limit intrusion of government and other entities on our personal lives and also wants to encourage free enterprise and the success of business and industry. Some of those forces may act against the ability to achieve optimal health outcomes,” said Dr. Steven Woolf of Virginia Commonwealth University, who served as chairman for the study panel.

The National Rifle Association did not immediately return calls seeking comment about the report, but in the past gun-rights advocates have fought any suggestion that firearms ownership has public health implications, and they have won cuts in the government’s budget for such research.

The researchers reviewed an array of studies over the years. They estimated that homicide and suicide together account for about a quarter of the years of life lost for U.S. men compared to those in those peer countries. Homicide, they noted, is the second leading cause of death among adolescents and young adults aged 15-24. The large majority of those homicides involve firearms.

The researchers said there is little evidence that violent acts occur more frequently in the United States than elsewhere. It’s the lethality of those attacks that stands out.

“One behavior that probably explains the excess lethality of violence and unintentional injuries in the United States is the widespread possession of firearms and the common practice of storing them (often unlocked) at home. The statistics are dramatic,” the report said.

For example, the United States has the highest rate of firearm ownership among peer countries — 89 civilian-owned firearms for every 100 Americans, and the U.S. is home to about 35 to 50 percent of the world’s civilian-owned firearms, the report noted.

Woolf said that researchers had expected that homicide would be an important factor in explaining the health disadvantage that existed in younger adults in the U.S., particularly among young men.

“The size of the health disadvantage was pretty stunning. The fact that our risk of death from homicide is seven times higher and from shootings 20 times higher is pretty dramatic, but I would add that was probably just as important to us was the extent of the health disadvantage in young Americans that had nothing to do with violent injuries.”

Woolf cited the statistics regarding premature babies and the high prevalence of illness among teenagers as equally disturbing as the statistics on guns and violence.