Objective: Exposure to certain metal(loid)s (MM) has been linked with dementia-related neuropathology, but many remain understudied. Furthermore, research on associations between plasma levels of MM and neuroimaging outcomes is sparse.

Methods: We assessed associations between plasma MM concentrations and later neuroimaging outcomes in 300 participants (mean age 65 (standard deviation [SD]: 6.6), 39% with >1 imaging timepoint) from the Emory Healthy Brain Study. Concentrations of 15 MM (arsenic (As), barium (Ba), beryllium (Be), cadmium (Cd), chromium (Cr), cobalt (Co), cesium (Cs), manganese (Mn), mercury (Hg), nickel (Ni), antimony (Sb), tin (Sn), tellurium (Te), uranium (U), and vanadium (V)) were quantified in plasma using inductively coupled plasma-mass spectrometry and dichotomized (detect/non-detect) based upon the limit of detection (LOD). Total grey matter volume, left and right white matter and hippocampus volumes, and left and right cortical thickness and volumes were measured using magnetic resonance imaging (MRI). Associations between MM detection and neuroimaging measures were assessed in single-pollutant mixed effects models adjusted for age, sex, race/ethnicity, education, and estimated total intracranial volume.

Results: Hg, Cr, Cd, Mn, and Ba had <3% of samples above the LOD so were excluded. Remaining 10 MM had frequencies of detection ranging from 4.0% (Cs) to 96.3% (U). We found variable associations between MM detection and cortical thickness (Sn: 0.49 SD higher left cortical thickness (95% confidence interval [CI]: 0.09, 0.89), Sb: -0.28 SD left cortical thickness (95% CI: -0.55, -0.01)). Nominally positive associations between Ni and white matter volume outcomes were observed; no other significant associations were observed.

Conclusion: In single-pollutant models, we found mixed associations between plasma MM and cortical thickness, but generally non-significant associations with other neuroimaging outcomes.