Guns, drugs and automobiles combine with poor diet and smoking to keep the average lifespan in the United States lower than similar nations in Europe and Asia.

The average American dies two years earlier than people in high-income nations in Europe and Asia.

And it’s not just because of poorer health and lifestyle choices. Guns, drugs and car crashes are also major contributing factors.

According to a new study, men in the United States live for an average of 76.4 years. Women, on average, live 81.2 years.

That compares to 78.6 years for men and 83.4 years for women in 12 other high-income countries.

Those nations are the United Kingdom, Japan, Germany, Italy, Austria, Denmark, Finland, Sweden, Norway, the Netherlands, Portugal, and Spain.

The findings were published Tuesday in the Journal of the American Medical Association (JAMA).

The report was compiled by researchers at the National Center for Health Statistics (NCHS) and Johns Hopkins Bloomberg School of Public Health.

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The researchers listed an array of reasons for the shorter average lifespan in the United States.

At the top were diet, tobacco, high blood pressure, and obesity.

However, the researchers also noted that 48 percent of the gap in lifespan between U.S. men and other countries was caused by drug poisonings, gun violence, and automobile crashes. Those three factors accounted for 19 percent of the gap for women.

Andrew Fenelon, a senior fellow at the NCHS and senior author of the story, told CNN he was “really surprised at just how large the contribution is” of these three causes of death.

Fenelon said the majority of drug-poisoning deaths are probably prescription opioid abuse and heroin use and are mostly accidental.

He also told CNN that the gun-related deaths are probably mostly suicides.

Car crashes are probably almost exclusively accidental, he said.

Ellen Meara, associate professor of health policy and clinical practice at the Dartmouth Institute for Health Policy and Clinical Practice, told CNN the causes of death aren’t surprising. But she noted this hasn’t always been the case.

Mears said that in the 1980s United States life expectancy compared more favorably with other countries. Since then, other countries have improved while the United States has stagnated or become worse.

“We have to look to see what we are doing or have been doing differently since the 1980s. It’s not like we can’t achieve what other countries have,” Meara told CNN.

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Experts say the United States could improve its life expectancy but it hasn’t taken the necessary policy steps.

Rebecca Cunningham, an emergency physician and director of the Injury Research Center at the University of Michigan, told the Chicago Tribune that “as a country, we have chosen not to by not investing the resources in injury prevention that would be needed. ”

She noted that other industrialized countries have a lower blood-alcohol limit for driving than the 0.08 percent in the United States. In addition, improvements to infrastructure to reduce traffic deaths haven’t been accomplished here.

Cunningham also told the Tribune that the United States hasn’t enacted the gun control and gun safety laws seen in other countries.

She added drug overdoses are affected by the U.S. medical community’s propensity to prescribe opioid painkillers.

In an opinion column in Bloomberg View, Christopher Flavelle writes that the single biggest difference between the United States and the other countries when it comes to life expectancy might be health insurance.

Flavelle said the portion of Americans who are uninsured or who are insured but lack access to quality care is a major factor in life expectancy.

“Policymakers can’t wave a wand and make Americans healthier,” Flavelle wrote. “They can get a step closer, however, by implementing a law that’s already on the books, that pays for itself, and that has a real chance of improving health.”

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