Drug and alcohol poisoning, suicide and liver disease are the main culprits of a recent decline in life expectancy for white Americans, according to a new report by the U.S. Centers for Disease Control and Prevention (CDC), reversing decades of medical progress made toward improving mortality rates across the country, PBS reports.

According to the study, which was recently published by the CDC’s National Center for Health Statistics, life expectancies for African Americans and Latinos have increased by 3.6 and 2.6 years, respectively, since the year 2000. However, among white Americans, improvements in mortality rates have been slowly flatlining. Between 2013 and 2014, researchers say life expectancy actually declined slightly among this group for the first time in more than two decades.

Delving deeper into the data, researchers found that between 2000 and 2015, unintentional poisonings from drugs and alcohol, suicide and chronic liver disease drove an astounding 28 percent increase in death rates among white Americans ages 25 to 34, as well as slighter increases in mortality for white people ages 35 to 54. Together, the increased death rates ultimately caused the expected life span for white Americans to decline, from 81.2 years down to 81.1 years overall.

The study echoes results published by Princeton University economists last fall that showed that mortality rates have been on the rise among middle-aged white Americans since 1999. Those researchers also noted that drugs and alcohol, suicide and liver disease were the main drivers of the downward trend, especially among less-educated white Americans.