We spend more on health care, per person, than any nation in the world. By far.

Read: Cancer rates down

And yet the United States still has a life expectancy is significantly lower than many other industrialized countries. Why?

Drugs, guns, and car crashes, says a new study.

The report, published in JAMA and authored by Dr. Andrew Fenelon of the National Center for Health Statistics, compared U.S. life expectancy to a dozen other first world countries, such as Austria, Spain, Japan and the United Kingdom.

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Men in the comparison countries lived an average of 2.2 years longer than American men (78.6 vs. 76.4). The exact same gap in life expectancy among women was observed (83.4 vs 81.2).

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In seeking an explanation to the disparity, Fenelon examined the three leading injury-related types of deaths in the U.S., all of which can have a major impact on average life expectancy because their victims are often very young.

Other potential drivers of shorter life expectancies, such as obesity and smoking, don’t typically cause death until middle age.

Overall, Americans are more likely to die of injuries than in every other country examined in the study.

While 6.3 out of every 100,000 Americans die in a car crash, only 1.7 for every 100,000 residents of the other countries meet the same fate.

For drug deaths, the disparity is even worse: 10.1 in the U.S. compared to 1.6 in the other 12 nations.

And of course, gun deaths are far more common here--2.9 per 100,000 people will die from a firearm injury in the U.S., compared to 0.1 in the other countries.

The difference in rate of injury-related deaths alone accounted for more than half of the life expectancy disparity between U.S. men and men in Portugal, Finland, Austria, Denmark, and Germany.

They accounted for more than 30 percent of the disparity between life expectancies for American women and women in the Netherlands, Denmark, and the U.K.