Epidemiology of Parkinson's disease and akinetic syndromes.

New reports of the incidence, prevalence and mortality of Parkinson's disease and parkinsonism are reviewed. Evidence for occupational and lifestyle risk factors and protective factors is updated. Recent genetic epidemiology studies of parkinsonism in twins and families, and studies that investigated imaging and physiologic markers of dopaminergic function in members without parkinsonism are presented.