Does cigarette smoking provoke Parkinson′s disease?

This is a review on cigarette smoking and Parkinson's disease (PD). The relationship between cigarette smoking and Parkinson's disease is very controversial. Cigarette smoking is an established risk factor for various diseases such as lung cancer, chronic obstructive pulmonary disease, and heart disease. However, beneficial effects have been debated over the years. It was in the late 1950's that studies reported a negative association between smoking and Parkinson's disease. More recently, several epidemiological studies have found a significant negative association between cigarette smoking and PD. That is, patients who smoke are 50% less likely to have PD when compared to their non-smoker counterparts. This suggests that cigarette smoking may have a neuroprotective effect on PD.