UPDATE 1-RESEARCH ALERT-Oppenheimer upgrades Apple

Jan 6 (Reuters) - Oppenheimer & Co upgraded Apple Inc (AAPL.O) to "outperform," saying a sudden change of leadership is not imminent, after the company's Chief Executive Steve Jobs said his weight loss was caused by a hormone imbalance that is relatively simple to treat.

In 2004, Jobs, 53, said he had undergone successful surgery to remove a rare type of pancreatic cancer.

Investors have been concerned about the cancer survivor's health after he appeared thin at a product launch in June.

In September, Jobs, who is often perceived as irreplaceable as Apple's leader, again appeared thin but jaunty as he introduced new iPod digital music players.

The brokerage said it seems unlikely that Jobs, the board, and its counsel would disclose the prognosis of a six-month recovery if it were at odds with doctors' expectations.

"The 'Apple Community' is now due an update in late spring, but until then the recovery will presumably be allowed to run its course without undue prying," the brokerage said.

However, Oppenheimer said it is still unsure whether Jobs is currently engaged in normal CEO duties.

The brokerage lowered it price target on the stock by $10 to $135.

Shares of Apple were up 2 percent at $96.15 in trading before the bell. They closed at $94.58 Monday on Nasdaq. (Reporting by Sandhya Menon in Bangalore; Editing by Anil D'Silva)