Jobs says he has 'hormone imbalance'

Apple CEO Steve Jobs has a hormone imbalance that is causing him to lose weight, he said in a letter posted Monday morning at the company's Web site in an attempt to squelch rumors about his health.

Questions about his health arose once again, after it was announced he would not be giving a keynote at Macworld Expo this week.

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Jobs underwent treatment for a rare form of pancreatic cancer in mid-2004 and rumors regarding his health have periodically captured headlines and the blogosphere ever since. Although pancreatic cancer is generally one of the more difficult types of the disease to recover from and has grim survival rates, Jobs has maintained that he had a less aggressive type of cancer and that it was successfully treated. However, over the past couple of years he has been noticeably thinner to the point of looking gaunt.

"Unfortunately, my decision to have Phil deliver the Macworld keynote has set off another flurry of rumors about my health, with some even publishing stories of me on my deathbed," reads the letter, which refers to Apple Vice President of Worldwide Product Marketing Phil Schiller, who is scheduled to give the keynote address Tuesday at Macworld Expo in San Francisco. "I've decided to share something very personal with the Apple community so that we can all relax and enjoy the show tomorrow," the letter continues.

Jobs acknowledged that he lost weight throughout last year and said that the reason "has been a mystery to me and my doctors," but that after "sophisticated blood tests" he was diagnosed with "a hormone imbalance that has been 'robbing' me of the proteins my body needs to be healthy." He has begun treatment, but because of how much weight and body mass he has lost it is expected to take until late spring before he has regained the weight he lost.

He will continue as Apple CEO during his recovery, Jobs wrote, closing the letter by saying he has said more than he wanted to about his medical condition and is not going to say anymore.

A statement from Apple's board also was posted on the company site reiterating a previous statement "if there ever comes a day when Steve wants to retire or for other reasons cannot continue to fulfill his duties as Apple's CEO, we will let you know."