The risk of Parkinson disease in Mediterranean people.

On the basis of previous epidemiologic studies, Parkinson disease was thought to be evenly distributed throughout the world. These studies, however, were conducted only on North European populations. The position with regard to the Mediterranean peoples was still unknown, and we therefore studied the frequency of Parkinson disease on the island of Sardinia, where some ethnic groups of the Mediterranean stock are represented. Based on 967 accepted cases, the prevalence 100,000 population on January 1, 1972, was 65.6; the average annual incidence for the period 1961 through 1971 was 4.9. These figures are one-half of the figures established for North Europeans. Our findings suggest racial differences in predisposition to Parkinson disease. Some Negroid features are present in Sardinians. If, as seems likely, Africans prove to be relatively unsusceptible to the disease, the risk for Sardinians and other Mediterranean ethnic groups might be intermediate between North Europeans and Africans.