According to the new study, the death rate from 2010 to 2017 for all causes among people ages 25 to 64 increased from 328.5 deaths per 100,000 people to 348.2 deaths per 100,000. It was clear statistically by 2014 that it was not just whites who were affected, but all racial and ethnic groups and that the main causes were drug overdoses, alcohol and suicides.

“The fact that it’s so expansive and involves so many causes of death — it’s saying that there’s something broader going on in our country,” said Ellen R. Meara, a professor of health policy at Dartmouth College. “This no longer limited to middle-aged whites.”

The states with the greatest relative increases in death rates among young and middle-aged adults were New Hampshire, Maine, Vermont, West Virginia and Ohio.

Dr. Woolf said one of the findings showed that the excess deaths were highly concentrated geographically, with fully a third of them in just four states: Ohio, Pennsylvania, Kentucky and Indiana.

“What’s not lost on us is what is going on in those states,” he said. “The history of when this health trend started happens to coincide with when these economic shifts began — the loss of manufacturing jobs and closure of steel mills and auto plants.”

For demographers like Kenneth Wachter, a professor emeritus at the University of California, Berkeley, the study’s findings are not surprising because there have been a number of similar reports. But, he said, “it is a valuable paper in bringing together these trends.”

The study leaves unanswered questions, including, Why is there an increased death rate only in the 25-to-64 age group?