Smokers at lower risk of Parkinson's

Smokers and those who breathe in 'second-hand' tobacco smoke are at significantly lower risk of developing Parkinson's disease than non-smokers, according to a new study.

Researchers led by a team at Queen Mary University of London found existing smokers are up to 50 per cent less likely to develop the degenerative illness, which now affects some 145,000 people in the UK – around one in every 350 adults.

The study, the biggest of its kind and based on data from more than 220,000 medical cases across eight countries, also found for the first time a relationship between passive smoking and a lower incidence of Parkinson’s. Those exposed to the cigarette smoke of others were 30 per cent less likely to develop the disease.

But while the research also found the more an individual smoked the lower their risk of Parkinson’s became, the authors of the study warned the “disastrous” harms caused by tobacco continue to vastly outweigh any benefit related to the neurological disease.

The scientists said their research should spur on efforts to identify and isolate what it was within cigarette smoke that was having the effect against Parkinson’s, with a view to developing a future preventive therapy.

Dr Valentina Goss, from Queen Mary University of London, said: “Our discovery is incredibly important from a scientific point of view and should prompt basic science research aimed at identifying the agent responsible for this effect found in tobacco. Hopefully this will give insight for preventive treatment options.

“However, no-one would ever be advised to use smoking as a preventive treatment for Parkinson’s based on this research because of the disastrous effects we know smoking has on people’s general health.” The statistical study published in the International Journal of Epidemiology looked at more than 700 comprehensive case histories of Parkinson’s disease found among a European database of 220,000 patients.

It found even those who had once smoked, but given up the habit were at lower risk from the illness with a 20 per cent reduction in cases compared to those who had never smoked. The study found the reductions in risk were broadly the same regardless of gender or socio-economic background. The research provides the strongest evidence yet for the long-suspected protective effects of tobacco against Parkinson’s, but the precise relationship between this effect and the chemicals in smoke remains unknown.

Many scientists believe the most likely chemical preventing or slowing the onset of the condition is nicotine, which stimulates production of dopamine, responsible for the brain’s pleasure response.