Overall life expectancy has dropped in the U.S. for three straight years, so it’s no longer surprising. However, unprecedented in a developed country not engaged in widespread war, and not matched by trends in similar countries, it is still shocking. Thankfully, it’s now less of a mystery.

That’s important, because the drop in life expectancy has not hit Americans uniformly. Any successful response must focus on the people who are feeling it the most — and must do so in a way that addresses the root causes at play.

Early deaths are on the rise particularly among those age 25-64. The increase is most prevalent in areas hardest hit by the Great Recession — one study found a third of early midlife deaths since 2010 occurred in Ohio, Pennsylvania, Kentucky and Indiana; Maine, too, has seen one of fastest increases, as has New Hampshire.

The meteoric rise of overdose deaths fueled by the opioid epidemic is a major factor, but not the only one. Also on the rise are deaths by suicide, alcohol and a range of diseases associated with obesity. Together, they are all sometimes referred to “deaths of despair.”

One report calls it a “broad erosion of health,” and it is indicative of something systemic affecting working-age adults. More and more, it seems that something is closely related to economic well-being.

We’ve pointed to this evidence before, and it keeps adding up. One new study, from researchers at University of Pennsylvania, Yale, Harvard and Massachusetts General Hospital, found that deaths from opioid overdose were far higher in areas that saw the closure of an auto manufacturing plant than those where a plant had remained open.

A second study adds to a growing body of work that suggests a link between good health and higher wages for low-wage workers. After controlling for state economy and welfare policies, the study estimated that a $1 increase in the minimum wage corresponds with a 3.5% decrease in suicide for Americans with a high school education or less, some of the hardest hit by the deaths of despair.

None of this research is definitive, but it is informative — it adds to our understanding of this massive, perplexing public health problem.

It shows that the health of Americans is tied to their ability to find work that brings in a sufficient paycheck — and perhaps provides a sense of personal satisfaction — and that failing to respond to a region’s economic distress can be deadly for its residents.

And it shows that the rising rates of suicide, substance use and obesity are related, and must be treated that way if we are to slow a public health crisis that is killing Americans too soon.