Federal Reserve Chair Janet Yellen testifies before a Senate Banking Committee hearing on the 'Semiannual Monetary Policy Report to the Congress' on Capitol Hill in Washington, July 13, 2017.

Federal Reserve Chair Janet Yellen just weighed in on the opioid crisis in the U.S.

In her testimony before the Senate Banking Committee on Thursday, Yellen said rampant opioid abuse in the U.S. is related to the decline in labor force participation among prime-age workers.

"I don't know if it's causal or symptomatic of long-running economic maladies that have affected these communities and particularly affected workers who have seen their job opportunities decline," Yellen said in response to questioning from Sen. Joe Donnelly, D-Ind., on the issue.

The United States is "the only advanced nation that I know of where in these communities we're actually, especially among less-educated men, seeing an increase in death rates partly reflecting opioid use," she added.

Death rate from drug abuse has exploded over the last 15 years

Source: Centers for Disease Control, Goldman Sachs Global Investment Research

Opioid overdose contributed to more than 33,000 deaths in 2015, according to the Centers for Disease Control and Prevention, and kills more than 90 Americans every day.