Exposure to neurotoxic metals and prevalence of parkinsonian syndromes in the province of Brescia (Northern Italy)

The prevalence of parkinsonian syndromes was studied in the province of Brescia (Northern Italy), in order to verify its possible increase in the surroundings of ferroalloy plants located in a valley of the pre-Alps. A case-list of subjects affected by these disturbances was identifted using four different sources of information: a) registers from local medical clinics; b) admission charts from local hospitals; c) consumption of levodopa; d) NHS list of exemption from prescription payment, due to the illness. Exploratory data show a frequency of parkinsonian disturbances among the residents in the surroundings of the ferroalloy plants and downwind (crude prevalence = 358/100.000 population, standardized for age and sex = 438) significantly higher (s.m.r. = 1.58; C.I.=1.41-1.76) than the entire Province (crude prevalence 246/100.000). This preliminary result could indicate the interaction of prolonged environmental exposure to heavy metals, such as manganese, and genetic factors, potentially relevant in this mountain population.