Apple CEO Steve Jobs said Wednesday in a company e-mail that he's going to take a medical leave of absence until June and that COO Tim Cook will take over day-to-day operations as interim CEO. The news is bound to set off speculation that Jobs won't be coming back.

In his last message right before MacWorld Jobs explained that his gaunt appearance was due to an undisclosed hormonal imbalance and that he would remain on the job while he recovers.

This time he said, "Unfortunately, the curiosity over my personal health continues to be a distraction not only for me and my family, but everyone else at Apple as well. In addition, during the past week I have learned that my health-related issues are more complex than I originally thought.

"In order to take myself out of the limelight and focus on my health, and to allow everyone at Apple to focus on delivering extraordinary products, I have decided to take a medical leave of absence until the end of June."

He said he expects to be "involved in major strategic decisions while I am out. Our board of directors fully supports this plan."