A new report finds drug overdoses are contributing to the increase in deaths among young and middle-aged adults, according to The Washington Post.

Other causes linked to the increase include suicide and liver disease. The findings, published in the Journal of the American Medical Association, come from an analysis of six decades of mortality data.

The largest relative increase in death rates from 2010 to 2017 was among people ages 25 to 34. According to study lead author Steven H. Woolf of Virginia Commonwealth University, the opioid epidemic is a major factor in the increase. However, improvements in life expectancy began to slow in the 1980s, long before the opioid crisis took hold in the United States, he noted.

“Some of it may be due to obesity, some of it may be due to drug addiction, some of it may be due to distracted driving from cellphones,” Woolf said.