Mark Zuckerberg's biggest surprise from his year of travels: the extent of the opioid crisis

Facebook CEO Mark Zuckerberg said the extent of the U.S. opioid crisis was the thing that surprised him the most during his travels throughout America this year.

"The biggest surprise by far is the extent of opioid issues, it's really saddening to see," Zuckerberg said during a live Facebook broadcast from the University of Kansas.

Zuckerberg grew emotional and had to pause to compose himself as he recounted talking to opioid addicts and the effects the epidemic has taken on them, their families and the country.

"One thing we don't fully internalize, how this epidemic has affected people's attitudes more broadly...it's one of the worst public health issues," he said.

Zuckerberg, the world's fifth-richest person, suggested the epidemic may have even impacted last year's election.

The issue is "so pervasive, it's affected attitudes on political issues more than people realize...counties that swung from Democrat to Republican were those with some of the highest opioid addiction rates," Zuckerberg said.

The opioid epidemic "is getting attention, but nowhere near what it needs. It's a public health crisis," he said.

Facebook has been widely criticized and last week faced tough questioning in Congress for allowing Russians to use its ad targeting to influence last year's election.

Despite this and other problems, Zuckerberg said he remains an optimist, pointing to the France, which had a drug epidemic problem a decade ago.

"It won't happen overnight, but there is a road map for how to improve."

"People who are addicted to opioids don't want to be," he said.

Zuckerberg also addressed the pervasive negative effects that economic globalization has had on some parts of the country he visited.

"When you lose a job, it doesn't just affect your family in the short term. It affects your view of what you want to do in the long term," he said.

Zuckerberg recounted a discussion he had with workers who had lost their jobs at a paper mill in Millinocket, Maine, after the work there moved across the border into Canada.

"People there were very entrepreneurial...but many of these folks were afraid the next job they would get would also be replaced," he said, decreasing the chances they would seek job re-training.