Apple chief executive and co-founder Steve Jobs is to take a medical leave of absence until June in an effort to escape the limelight while he recovers his health.

Jobs explained in an open letter to employees that the health problems which had been causing him to lose weight were more serious than originally thought.

"Unfortunately, the curiosity over my personal health continues to be a distraction not only for me and my family, but for everyone else at Apple as well," Jobs wrote.

"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."

Chief operating officer Tim Cook will take over the day-to-day operations of the company while Jobs is away. A long-time Apple executive, Cook is believed by many to be the eventual successor to Jobs.

Jobs said that, although he will not be dealing with daily aspects of the company's operation, he will still handle major company decisions during his absence.

"Our board of directors fully supports this plan," he wrote. "I look forward to seeing all of you this summer."

The move follows months of speculation on Jobs's health. Having beaten pancreatic cancer in 2004, he began to show noticeable weight loss in his public appearances throughout 2008.

Rumours of declining health were further sparked when the company announced in December that marketing head Phillip Schiller would give the keynote address at the annual Macworld Expo.

The speculation spurred Jobs to admit that the weight loss was due to a hormonal imbalance.