The medical world recently discovered that cigarette smoke decreases the risk of getting the degenerative neurological condition - but the genes responsible were a mystery.
US geneticist Professor Jeffrey Vance, from Duke University in North Carolina, has told the International Congress of Human Genetics in Brisbane he has found a gene that helps explain the link.
The gene - known as NOS2A - is found in every cell of the body and is responsible for the production of nitric oxide.
If too much is produced brain cells can die, leading to neuro-degenerative diseases like Parkinson's and Alzheimer's.
Prof Vance and his team realised that while everyone has this gene, in smokers it appeared to be "turned down", limiting cell death and ultimately disease.
"We think that something in smoke keeps the level of the NOS2A down so cells don't produce nitric oxide, which decreases cell damage," he told AAP.
The researcher was not sure why this was but said the team would look closer at this area of DNA to try to better understand the link.
"It really is ironic that something good might ultimately come out of smoking," Prof Vance said.
"It is definitely a window of opportunity that we are working on."
But the main focus on his project was on further understanding Parkinson's disease, which affects about 40,000 Australians, most aged over 60.
The cause is unknown and while there are treatments available including surgery and medication to replace the missing chemical dopamine, these have a limited effect.
"The other problem is that these things are not curing anything, only treating the symptoms while the process is still going on," Prof Vance said.
His team is now using this genetic information to try and find a way to slow down Parkinson's disease, or even prevent it.
"I'd like to be able to identify people that are at a high risk of Parkinson's disease so we can provide them information to change their lifestyle or give them a drug to stop them getting it," the scientist said.
Until is is possible to match smokers to nonsmokers by genetic traits, it won't be clear whether smoking is protective or a marker of those less susceptible.
I notice that this professor is from Duke University, named after a notorious tobacco marketer. North Carolina has a
concentration of tobacco interests. In the case of this study, one needs to follow the money. I don't think it is
deliberate psychopathy, merely defacto.
BTW, cigarette smoke is a particularly harmful way to deliver nicotine. Smokeless tobacco has 5% of the risk of cigarettes.
Unfortunately, smoke delivers acetylaldehyde. The brain converts this into a substance more addicting than heroin. For
this reason smokeless doesn't adequately substitute for cigarettes for most people.
Those who are primarily addicted to nicotine will be able to use smokeless while others will find it very unsatisfying. This
also explains why Electronic cigarettes don't satisfy many users.
I have noticed that those who oppose tobacco aren't interested in safer tobacco. While it may be wrong to advertise "safe"
tobacco, for those who are interested in public health safer "unsafe" products should be of great interest. This'
is particularly true if it is impossible to reach a zero exposure level