Kaiser Permanente's chief executive and chairman, Bernard J. Tyson, died in his sleep early Sunday at age 60, the California-based company confirmed.

Tyson succeeded George Halvorson as chief executive in 2013 and had led the health care corporation for the last six years. Tyson was the company's first black chief executive since it was founded in 1945.

His cause of death is unclear.

In its statement, Kaiser Permanente described Tyson as an "outstanding leader, visionary and champion for high-quality, affordable health care."

Kaiser Permanente Chief Executive Bernard Tyson in an undated photo. Kaiser Permanente

Executive Vice President and Group President Greg Adams will serve as interim chairman and chief executive.

"Bernard was an exceptional colleague, a passionate leader, and an honorable man. We will greatly miss him," board member Edward Pei said. "The board has full confidence in Greg Adams' ability to lead Kaiser Permanente through this unexpected transition."

Tyson spent 34 years with Kaiser Permanente in various roles, including as a hospital administrator, according to his company biography. The San Francisco Bay Area native received a bachelor's degree in health service management from Golden Gate University in San Francisco and held a number of roles in the community.

He was a member of the Business Council and the Bay Area Council and was on the board of directors of the American Heart Association, the biography said.