(Reuters) - Bernard J. Tyson, chairman and chief executive officer of not-for-profit health insurer Kaiser Permanente, died unexpectedly in his sleep on Sunday, aged 60, the company said in a statement.
Tyson, who held the top job since 2013, was Oakland, California-based Kaiser Permanente's first black chief executive and a strong proponent for affordable and accessible healthcare.
The company did not give a cause of death. A company spokesperson did not immediately respond to a request for comment.
A day earlier on Saturday, the San Francisco native took to Twitter to post about "high-tech and high-touch" healthcare.
Tyson was described by colleagues in a company statement as "an outstanding leader, visionary and champion for high-quality, affordable health care for all Americans."
Kaiser's annual operating revenue as of June was nearly $80 billion, up from about $53 billion in 2013 when Tyson took over as CEO, according to the company's website.
The company, which serves more than 12 million people across the United States and was founded in 1945, named Gregory Adams, executive vice president, as interim chairman and CEO.
(Reporting by Melissa Fares in New York; editing by Richard Pullin)