While sucking on a cigarette definitely is bad for your health, numerous non-smokers may find themselves some day being prescribed nicotine patches to combat Alzheimer's disease.

In a soon-to-be-published study, scientists in North Carolina will describe how they tested the patches on 11 senior men and women to counter deteriorating memories.

After several weeks of treatment, the subjects experienced significant improvements in their abilities to make decisions quickly and recognize objects.

The researchers are so impressed with the results that they propose a long-term, multisite study involving a large number of seniors whose memories are frayed.

As well, researchers at the University of Manitoba have published material detailing nicotine's ability to combat the effects in nerve cells of one of the substances believed to cause Alzheimer's.

"The concept is the same as the effect of Aspirin on inflammation," said Daniel Sitar, lead U of M researcher.

U.S. and European studies published over the past year indicate that nicotine has a protective effect in laboratory animals whose conditions mimic those resulting from Alzheimer's.

Said Paul Fraser, a researcher with the Centre for Research in Neurodegenerative Diseases at the University of Toronto, "The definitive animal experiment has already been done in Sweden."

All this research reinforces the results of small studies on humans by Edward Levin at Duke University's Medical Center laboratory, which found that using nicotine patches on people with Alzheimer's reduced some of their mistakes by 10 to 80 per cent.

Despite the encouraging data, some researchers are concerned that the public might misinterpret the results.

In particular, they fear that some will conclude smoking is beneficial.

"By no means am I encouraging anyone to take up smoking or to continue smoking because clearly the adverse consequences of smoking outweigh any cognitive improvement," Prof. Levin said.

Ken Kellar, a Georgetown University professor in Washington, who hopes to collaborate with Prof. Levin on the large study, noted: "Smoking cuts life expectancy by seven or eight years, and some would argue that that is a way of getting rid of Alzheimer's patients before they come down with the disease."

Still another cause for going slow is confusing epidemiological data.

Initially, it was thought that half as many smokers as non-smokers came down with Alzheimer's.

But several recent analyses of Alzheimer's data has turned up neither a positive nor a negative connection.

But proponents of nicotine as a brain medicinal argue that this shows only that the bad features of smoking cancel any good effects of nicotine.

Some scientists said a lack of funding is part of the reason there have been no large trials examining the nicotine-patch effect on a disease such as Alzheimer's.

Because nicotine is in the public domain, the drug's new medical uses cannot be patented.

"We could have had answers 10 years ago to the question of whether it is good for Alzheimer's if drug companies had given a go on it," Prof. Kellar said.

Instead, several drug companies are trying to develop nicotine look-alikes that they can patent, Prof. Levin said.

The arrival of these look-alikes or a test proving the long-term efficacy of nicotine patches for elderly patients is some time away.

"It's really heart-rending when you get a call from someone who wants to know whether to use the patch, and you have to say [that] in a couple of years we will have a better answer for you," Dr. Levin said.

"It's especially hard when they say, 'But my grandmother has Alzheimer's now.' "