Apple's iconic chief executive Steve Jobs, following months of speculation about his health, has announced he is being treated for a "hormone imbalance" but would remain head of the company.
Jobs, 53, in a letter to the "Apple Community," noted that his recent weight loss and decision not to give the keynote presentation at the annual Macworld convention opening in San Francisco on Tuesday had set off a "flurry of rumours about my health, with some even publishing stories of me on my deathbed."
"I've decided to share something very personal with the Apple community so that we can all relax and enjoy the show tomorrow," said Jobs, co-founder of the California company behind the Macintosh computer, iPhone and iPod.
"As many of you know, I have been losing weight throughout 2008," said Jobs, who underwent surgery for pancreatic cancer in 2004 and looked extremely gaunt at his last public appearance several months ago.
"The reason has been a mystery to me and my doctors," the Apple CEO said. "A few weeks ago, I decided that getting to the root cause of this and reversing it needed to become my number one priority.
"Fortunately, after further testing, my doctors think they have found the cause a hormone imbalance that has been 'robbing' me of the proteins my body needs to be healthy," Jobs said.
"Sophisticated blood tests have confirmed this diagnosis," he said. "The remedy for this nutritional problem is relatively simple and straightforward, and I've already begun treatment.
"But, just like I didn't lose this much weight and body mass in a week or a month, my doctors expect it will take me until late this Spring to regain it," Jobs said, adding: "I will continue as Apple's CEO during my recovery."
The Apple chief said he "will be the first one to step up and tell our board of directors if I can no longer continue to fulfill my duties as Apple's CEO.
"I hope the Apple community will support me in my recovery and know that I will always put what is best for Apple first," he said. "So now I've said more than I wanted to say, and all that I am going to say, about this."
In a statement released simultaneously with Jobs's letter, the Apple board said "it is widely recognized both inside and outside of Apple that Steve Jobs is one of the most talented and effective CEOs in the world.
"As we have said before, 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, you will know it.
"Apple is very lucky to have Steve as its leader and CEO, and he deserves our complete and unwavering support during his recuperation. He most certainly has that from Apple and its board."
Apple's share price rose 2.99 percent to US$93.46 dollars in New York following the announcement about Jobs's health.
Apple has been notoriously secretive about Jobs's health and the company came in for some criticism for failing to acknowledge his medical issues sooner.
"It's an announcement that could have been made last month and, given the way that Jobs and Apple have traded on his reputation to pitch the company, it should have been," wrote Staci Kramer on paidContent.org.
Speculation about Jobs's health had been rampant since it was announced last month that for the first time in 11 years he would not give the keynote speech at Macworld, the annual cult-like gathering of Apple devotees.
Marketing vice president Phil Schiller is to give the keynote at Macworld, which runs from January 6-9 and features more than 450 companies promoting gadgets, gear, software or services tailored for Apple products.
Born in San Francisco on February 24, 1955 to a single mother and adopted at a young age, Jobs founded Apple with engineer Steve Wozniak after dropping out of college.
He left the company in 1985 after an internal power struggle but returned in 1996 and is credited with reversing Apple's fortunes by launching the iPod MP3 player and the iPhone.
Under Jobs, Apple has also made its Macintosh computers more compatible with Windows-based PC programs and boosted its share of a market long ruled by machines based on Microsoft software.