Long Term Exposure to Manganese in Rural Well Water Has No Neurological Effects

BACKGROUND There is debate on the neurological impact of chronic exposure to Manganese (MN). METHODS MN burden from rural well water was studied cross-sectionally in two proband cohorts from rural dwellings located in northern Germany. Both cohorts had exposure times for up to 40 years and were separated on the basis of well water MN content. Group A (41 subjects; mean age 57.5 years) was exposed to MN water contents of at least 0.300 mg/l (range 0.300 to 2.160), while group B (74 subjects; mean age 56.9 years) was exposed to concentrations of less than 0.050 mg/l. Both proband groups were homogenous with regard to age, sex, nutritional habits, and drug intake. Neurological assessments by clinical investigators blinded for proband's exposure status was done using structured questionnaires, standardized neurological examination with assessment of possible Parkinsonian signs by the Columbia University Rating Scale, and instrumental tests of fine motor coordination. RESULTS No significant difference in any neurological measure was found between groups. Results were not confounded by demographic and dietary features. CONCLUSION Exposure to high body burden of MN does not result in detectable neurological impairment. Exposure to MN in drinking water does not seem to be a risk factor for idiopathic Parkinson's disease.