The report, published in the Journal of the American Medical Association, was immediately hailed by outside researchers for its comprehensive treatment of a still-enigmatic trend: the reversal of historical patterns in longevity.

Despite spending more on health care than any other country, the United States has seen increasing mortality and falling life expectancy for people ages 25 to 64, who should be in the prime of their lives. In contrast, other wealthy nations have generally experienced continued progress in extending longevity. Although earlier research emphasized rising mortality among non-Hispanic whites in the U.S., the broad trend detailed in this study cuts across gender, racial and ethnic lines. By age group, the highest relative jump in death rates from 2010 to 2017 — 29 percent — has been among people ages 25 to 34.