[Smoking and Parkinson's disease].

Reports that tobacco smokers are at a lower risk of incurring Parkinson's disease (PD) than are non smokers and that a high percentage of Parkinsonians stop smoking before the onset of the disease, were reinvestigated by study of 110 hospital patients with PD and 110 other patients. In contrast to controls, fewer patients ever smoked cigarettes (39.1% versus 7.3%); moreover, many Parkinsonians (82%) stopped smoking before the onset of the disease. The high percentage of patients with PD who stopped smoking might by explained by premorbid behavioural modifications related to the biochemical cerebral changes already present in the preclinical stage of the disease.