Steve Jobs's decision to take time away from Apple to deal with his health problems has once again raised the question of who his long-term successor might be – but it has also left concerns about the company's approach.

Although there are no laws governing whether a corporation's senior executives should disclose their health problems, some believe that the exalted status that Jobs holds within Apple means Wall Street deserves better information. And particularly puzzling is that the news comes just a week after Jobs – an intensely private man - surprised the industry by suddenly revealing that his recent weight loss was the result of a hormonal problem.

Jobs's initial health statement was made on the eve of Macworld Expo, an event at which the company traditionally unveils its latest products. The show has become massively important to Apple investors, with the company's stock leaping after the announcements by as much as 14% in recent years.

That announcement helped quieten frantic speculation regarding his decision to pull out of the speech, but the short time between the two statements has left some confused by Apple's behaviour.

"They'll tell you the least they can tell you," Roger Kay, an industry analyst with Endpoint, told Associated Press. "They're trying to have it both ways, to protect their guy's privacy and feelings and at the same time somehow signal the market," said Kay.

An Apple spokesman responded by referring to an email sent to Apple staff by Jobs, in which he said that he discovered the broader scope of his health problems "during the past week".

Answering the questions about Jobs's long-term successor is no more straightforward. Several names have been mentioned as potential candidates, but for now the only hard signal is that his temporary replacement will be Tim Cook, the company's meticulous and demanding chief operating officer.

Without more details, it is impossible to know how serious Jobs's latest illness is – but history would suggest that it is far from insignificant.

His previous decision to relinquish control came only after an 18-month battle with cancer, which he had tried to treat with a homeopathic diet before finally agreeing to undergo surgery and hand over temporary control of Apple to someone else.

Even at that point Jobs took just a few weeks off work - far less than the five months announced today.

Apple pundit John Gruber, writing on his popular blog Daring Fireball, said that the latest development was "worrisome".

"It's very difficult to read this any other way than that where Jobs says 'more complex', he means 'worse'."