A surge in drug overdoses in suburban areas is largely responsible for a rise in premature deaths among adults ages 25-44 in 2015, according to a new report.

The findings come from the Robert Wood Johnson Foundation, which compared counties within each state on more than 30 health-influencing factors such as education, jobs, and housing.

Drug deaths are also increasing among 15- to 24-year-olds, but almost three times as many people in this age group die by homicide, suicide or in motor vehicle crashes, USA Today reports.

A decade ago, suburbs had the lowest rate of premature deaths due to drug overdoses, but now they have the highest, the researchers said. “Smaller metro and rural counties also have higher rates of premature death due to drug overdoses,” the researchers noted in a news release.