Epidemiology of multiple system atrophy

Multiple system atrophy (MSA) is a form of atypical parkinsonism with unkno wn etiology. The epidemiological studies conducted up to now on this diseas e are scarce. The incidence rate is about 0.6 cases per 100 000 persons per year. The prevalence rates show 4-5 cases per 100 000 persons. In Italy, a bout 4900 prevalent cases have been estimated. The mean onset age is about 54 years; the median survival is 7-9 years. Only one case-control study has been performed on this disease. This study showed an increased risk of MSA associated with occupational exposure to organic solvents, plastic monomer s and additives, pesticides and metals. Smoking habits seem to be less freq uent in MSA cases (as in Parkinson's disease cases) than in healthy control s. Quinn's clinical criteria and those of the Consensus Conference promoted by the American Academy of Neurology are in fair agreement. We have perfor med a case-control study on 73 MSA cases, 146 hospital controls and 73 popu lation controls.