EMBARGOED FOR RELEASE UNTIL 4 PM ET, March 10, 2010
Years of Smoking Associated with Lower Parkinson鈥檚 Risk, Not Number of Cigarettes Per Day
ST. PAUL, Minn. -
Researchers have new insight into the relationship between Parkinson鈥檚 disease and smoking. Several studies have shown that smokers have a lower risk of developing Parkinson鈥檚 disease. A new study published in the March 10, 2010, online issue of , the medical journal of the , shows that smoking for a greater number of years may reduce the risk of the disease, but smoking a larger number of cigarettes per day may not reduce the risk. 鈥淭hese results could guide the development of studies on various tobacco components with animal models to help understand the relationship between smoking and Parkinson鈥檚 disease,鈥 said study author Honglei Chen, MD, PhD, of the National Institute of Environmental Health Sciences in Research Triangle Park, N.C. 鈥淩esearch to reveal the underlying chemicals and mechanisms is warranted; such studies may lead to a better understanding of the causes of Parkinson鈥檚 disease. However, given the many adverse consequences of smoking, no one would suggest smoking in order to prevent Parkinson鈥檚 disease.鈥 The study involved 305,468 AARP members age 50 to 71 who completed a survey on diet and lifestyle at the time and again about 10 years later. During that time, 1,662 of the people had developed Parkinson鈥檚 disease, or about one-half of one percent. Current smokers were 44 percent less likely to develop Parkinson鈥檚 disease than people who had never smoked. People who had smoked in the past and quit were 22 percent less likely to develop Parkinson鈥檚 than people who had never smoked. People who smoked for 40 or more years were 46 percent less likely to develop Parkinson鈥檚 disease than people who never smoked. Those who smoked for 30 to 39 years were 35 percent less likely to have the disease than nonsmokers. In contrast, those who smoked for one to nine years were only eight percent less likely to get the disease. The risk of developing Parkinson鈥檚 disease did not change based on how many cigarettes a person smoked per day. Chen noted that studies have shown that smoking is not associated with a slower progression of the disease once Parkinson鈥檚 develops or a reduced risk of death, so he said there is no evidence to support the use of nicotine or other smoking-related chemicals in treating the disease. The study was supported by the National Institutes of Health, the National Institute of Environmental Health Sciences and the National Cancer Institute.