A new study adds to the previously reported evidence that cigarette smoking protects against Parkinson's disease. Specifically, the new research shows a temporal relationship between smoking and reduced riskof Parkinson's disease. That is, the protective effect wanes after smokers quit.

As reported in the March 6 issue of Neurology, Thacker and colleagues analyzed data, including detailed lifetime smoking histories, from 79,977 women and 63,348 men participating in the Cancer Prevention Study II Nutrition Cohort. During about 9 years of follow-up, 413 subjects developed definite or probable Parkinson's disease.

Compared to people who had never smoked and were considered to have "normal" Parkinson's disease risk, former smokers had a 22-percent lower risk of Parkinson's disease and current smokers had a 73-percent lower risk. "The results were similar for men and women, and were also similar to the results of studies by many other researchers looking at the same topic," Thacker noted.

More information: http://www.tcmadvisory.com/2007/3-22/200732214328.html