Changing epidemiology of Parkinson's disease: predicted effects of levodopa treatment.

Recent studies suggest that levodopa treatment reduces the excess mortality due to Parkinson's disease, found to be three times that expected in the general population. This will affect the equilibrium state of the epidemiology of Parkinson's disease. The predicted increase in prevalence of Parkinson's disease was calculated according to two mortality patterns, one the same as expected in the general population and the other 1.5 times that expected; the proportional increase in prevalence is 1.8 and 1.4, respectively. The predicted increase in the duration of the disease if 6.3 or 3.2 years. As a consequence, there will be an increase of patients with long-term levodopa treatment difficulties, and with Parkinson's disease symptoms not treatable with levodopa, e.g. dementia. This seriously warrants the research of new approaches in the treatment of Parkinson's disease.