Smoking and drinking lots of coffee may protect against Parkinson's disease

In what must be a rare example of smoking supposedly providing some benefit, researchers in the U.S. say in families with a history of Parkinson's disease, those who smoke cigarettes and drink lots of coffee appear to reduce their risk of developing the disease.

The researchers from Duke University Medical Center reached this conclusion as a result of a study of 356 Parkinson's disease patients and 317 family members without the disease.

They believe the findings suggest that both genetic and environmental factors may influence the development of Parkinson's, a theory supported by previous research which also suggests that smokers and coffee drinkers have a lower risk of developing Parkinson's disease.

Parkinson's disease is a progressive neurodegenerative disease characterised by trembling in the arms and legs, stiffness and rigidity of the muscles and slowness of movement.

The study by the Duke University researchers is the first to specifically examine the impact of cigarette smoking and caffeine consumption within families affected by the disease.

By studying individuals with Parkinson's disease and their families scientists are able to limit the number of unknown genetic and environmental factors influencing the development of the condition.

The researchers however do caution that smoking cigarettes and consuming large amounts of caffeine carry their own risks and should not be taken up in an attempt to avoid developing Parkinson's disease.

The authors say they found individuals with Parkinson's disease were half as likely to report ever smoking and a third as likely to report current smoking compared with unaffected relatives, and were also less likely to drink large amounts of coffee.

The researchers say the biological mechanisms through which smoking and caffeine work in individuals at risk of Parkinson's disease remains unclear and further research is needed to clarify how they may modify the existing underlying genetic susceptibilities.

According to background information in the article taking non-steroidal anti-inflammatory (NSAID) medications (such as aspirin, ibuprofen and naproxen) also possibly offers some protection to individuals at risk of developing Parkinson's disease, however this study found no link between NSAID use and Parkinson's disease.

The research team say the complexity of Parkinson's disease suggests such environmental factors do not work in isolation, but highlights the importance of gene-environment interactions in deciding the susceptibility for Parkinson's disease.

The research was supported by grants from the National Institute of Neurological Disorders and Stroke, National Institutes of Health and is published in the current issue of the Archives of Neurology, one of the JAMA/Archives journals.