Contrary to last week’s reports that Steve Jobs has a “treatable hormone imbalance”, the Apple founder and CEO today circulated an email to employees saying his health issues are more complex than he initially thought, and he is taking medical leave until June.

The email was released after markets closed, and announced that Apple chief operating officer Tim Cook will take over day-to-day operations from Mr Jobs.

“As CEO, I plan to remain involved in major strategic decisions while I am out,” Mr. Jobs added. “Our board of directors fully supports this plan.”

After hours trading in Apple shares was halted as the news was released.

In the letter 53-year-old Mr Jobs said curiosity over his personal health “continues to be a distraction not only for me and my family, but everyone else at Apple as well.”

Last week’s announcement of his alleged hormone deficiency being the cause of his dramatic weight loss provided so few details that it incited further questions about his health.

While Mr Jobs spoke at the Apple Worldwide Developers Conference in June, he did not even attend the final Macworld for Apple earlier this month at which he traditionally gives the keynote speech, spurring new speculation about his health.

A fight with pancreatic cancer in 2004 that was successfully treated with surgery has seen Mr Jobs’ health keenly scrutinised ever since.

Apple shares are currently down on the Nasdaq 2.71% to $85.33.

The full text of the letter was released by Apple:

Team,
I am sure all of you saw my letter last week sharing something very personal with the Apple community. 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.

I have asked Tim Cook to be responsible for Apple’s day to day operations, and I know he and the rest of the executive management team will do a great job.

As CEO, I plan to remain involved in major strategic decisions while I am out.

Our board of directors fully supports this plan.

I look forward to seeing all of you this summer.

Steve