Apple shares down after Jobs' reversal on health

Since then, under Jobs' demanding leadership, Apple has churned out a string of sleek gadgets, from the iMac and the iPod to a new line of aluminum-covered Macbooks and the coveted iPhone. Many investors fear that without Jobs, Apple would not be able to sustain its growth or its high-end minimalist style.

Last week, Jobs said his disclosure of his hormone problem was "more than I wanted to say, and all that I am going to say" about his health. It came on the eve of Macworld, the biggest Apple trade show of the year, at which Jobs traditionally delivered the keynote address to avid fans. In December, Apple said Jobs would not take the stage as usual, stoking more rumors and prompting Jobs' Jan. 5 letter, which he said he hoped would allow everyone to relax.

The limited amount of information in that announcement and Wednesday's update left medical experts guessing. Some specialists said Jobs' past pancreatic cancer could be the problem, given the organ's role in digestion and nutrition.

Apple's overall secrecy and its history of keeping information about Jobs' health under wraps is only increasing the speculation. The company waited until after Jobs underwent surgery in 2004 to treat a very rare form of pancreatic cancer — an islet cell neuroendocrine tumor — before alerting investors. That type of cancer is easily cured if diagnosed early, unlike the deadlier and more common adenocarcinoma.

And last summer, Cupertino, Calif.-based Apple insisted Jobs' weight loss was due to a common bug.

The New York Times reported Thursday, citing two undisclosed people familiar with Jobs' condition, that Jobs was not suffering from a recurrence of cancer, but that his body was having trouble absorbing food.