LAUSR

Occupational aluminum (Al) exposure is linked to mild cognitive impairment (MCI), yet its neuroanatomical mechanisms remain unclear. We investigated gray matter volume (GMV) alterations specifically associated with Al-induced MCI. This study enrolled 86 participants: 30 Al-exposed MCI (Al-MCI), 26 Al-exposed cognitively normal (Al-HC), and 30 non-exposed controls (Non-Al-HC). Structural MRI quantified whole-brain GMV. Plasma Al concentrations, Montreal Cognitive Assessment (MoCA), the Rey Auditory Verbal Learning Test (AVLT), and the Trail Making Test (TMT) were assessed in Al-exposed individuals. Intergroup GMV differences were analyzed via ANCOVA. Partial correlations and mediation analyses explored cognition-GMV relationships. We found that Al-MCI and Al-HC showed comparable plasma Al concentrations (42.74 ± 26.00 vs. 32.52 ± 30.86 µg/L, p = 0.184). A graded pattern of bilateral caudate nucleus (CAU) atrophy was observed: most severe atrophy in the Al-MCI group, intermediate atrophy in the Al-HC group, and the largest volumes in the Non-Al-HC group (p < 0.05 for all pairwise comparisons). In Al-exposed individuals, left CAU volume correlated positively with abstraction (r = 0.294, p = 0.028), language (r = 0.321, p = 0.016), and AVLT-immediate recall (r = 0.289, p = 0.030). Right CAU volume correlated negatively with TMT-A error responses (r=-0.306, p = 0.022). In conclusions, CAU atrophy was significantly associated with cognitive decline and may represent a specific neuroimaging feature of occupational Al-induced MCI.