Death rates for Americans with at least a bachelor's degree continued to fall.

(Bloomberg) — Middle-aged, non-Hispanic white Americans saw a “marked increase” in mortality between 1999 and 2013, a reversal from a decades-long decline that can be largely explained by a spike in suicide, substance abuse and liver disease, new research shows.

“No other rich country saw a similar turnaround,” Angus Deaton, the Princeton University professor who won this year’s Nobel Prize in economics, and co-author Anne Case write in a study dated Sept. 17. “Although all education groups saw increases in mortality from suicide and poisonings, and an overall increase in external cause mortality, those with less education saw the most marked increases.”

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The change in overall mortality was driven by those with a high-school degree or less, the study found, drawing from sources including data from the Centers for Disease Control and Prevention and the Census Bureau. Those with a bachelor’s degree or higher saw death rates fall — though they too posted an increase in mortality from suicide and drug and alcohol poisonings.

The authors note that the period coincided with an era of increased use of prescription pain-killers and came at a time when white, middle-aged Americans increasingly reported being in pain and poor health in self-assessment surveys. They also say economics could have been a driver in the change.

“Although the epidemic of pain, suicide, and drug overdoses preceded the financial crisis, ties to economic insecurity are possible,” they write. “After the productivity slowdown in the early 1970s, and with widening income inequality, many of the baby-boom generation are the first to find, in midlife, that they will not be better off than were their parents.”

Regardless of what’s behind the incompletely understood epidemic, it’s cause for concern, they conclude.

“A serious concern is that those currently in midlife will age into Medicare in worse health than the currently elderly,” they write, and “addictions are hard to treat and pain is hard to control, so those currently in midlife may be a ‘lost generation’ whose future is less bright than those who preceded them.”

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