Health care provider Kaiser Permanente said Sunday its chairman and CEO, Bernard J. Tyson, has died unexpectedly at the age of 60.

No other details were provided in the company’s announcement, which said that Tyson died in his sleep early Sunday.

He was the first African-American to head the company as CEO when he took that position in 2013.

Tyson is survived by his wife, Denise Bradley-Tyson, and three sons, Bernard J. Tyson Jr., Alexander and Charles.

The board of directors has named Executive Vice President Gregory Adams as interim chairman and CEO.

Tyson, who worked at Kaiser Permanente for more than 30 years in roles including hospital administrator and chief operating officer, had been on Time magazine’s list of the world’s most influential people and one of the “Health Care 50.”

Executive Committee Chair Edward Pei called Tyson “an exceptional colleague, a passionate leader and an honorable man.”

“We will greatly miss him,” Pei said in the company’s news release. He added that the board “has full confidence in Greg Adams’ ability to lead Kaiser Permanente through this unexpected transition.”

Oakland, California-based Kaiser Permanente grew under Tyson’s leadership from 9.1 million members and 174,000 employees to 12.3 million members and 218,000 employees, according to the company. Its network of 17,000 physicians grew to 23,000, and annual revenue increased from $53 billion to more than $82.8 billion.

Tyson also was on the boards of the American Heart Association and Salesforce. He was a member of the American Academy of Arts and Sciences, and deputy chairman of the Americas of the International Federation of Health Plans.

A native of the San Francisco Bay area, Tyson received a bachelor’s degree in health service management and an MBA in health service administration from Golden Gate University in San Francisco.

While at Kaiser Permanente, he was a member of the Bay Area Council, a business-led public policy organization advocating for a strong economy for area residents.