Cognitive impairment in an adult Mexican population non-occupationally exposed to manganese.

We examined the association between non-occupational exposure to Mn and cognitive functions. The study was carried out in a mining district located in Hidalgo State, Mexico, with 288 adults. Air and blood Mn concentrations were determined, and neuropsychological tests were administered to explore cognitive functions and depression. Blood Mn mean was 9.5 ± 4.14 μg/L. A total of 73% of the study group were in contact with air Mn levels that surpassed the EPA recommended guideline level for non-occupational environments (0.05 μg/m(3)). Air Mn concentration was associated as a risk factor for attention impairment (OR=1.75, 95% CI: 1.01-3.06). Blood Mn levels were not associated to any of the measured outcomes. The main finding of this study is the presence of attention impairments associated to high levels of air Mn exposure. These results confirm previous studies, in which cognitive impairment is reported for exposed population.