A great deal of research has been devoted to identifying subclinical functional brain abnormalities in manganese (Mn)-exposed welders. However, no previous study has investigated morphological brain abnormalities, such as changes in brain volume, in welders. This study evaluates morphological changes in brain volume among welders, and investigates the relationship between structural brain abnormalities and subclinical dysfunction in this population.Methods
We used voxel-based morphometry (VBM) to assess differences in gray and white matter brain volumes between 40 welders with chronic Mn exposure and 26 age-matched control subjects. Correlation analyses were used to investigate the relationship between brain volume changes and decreased performance on neurobehavioral tests.Results
Brain volumes in the globus pallidus and cerebellar regions were significantly diminished in welders with chronic Mn exposure compared to controls (FDR-corrected P < 0.05). These changes in brain volume were negatively correlated with cognitive performance and grooved pegboard scores.Conclusion
There are measurable brain volume reductions in the globus pallidus and cerebellum of welders chronically exposed to Mn, and these volume reductions correlate with cognitive and motor neurobehavioral deficits. Our findings therefore indicate that volumetric measurement could be a useful subclinical marker among welders that show no signs of manganism.