Brain functional connectivity network alterations in occupational aluminum exposure among workers with mild cognitive...

Increasing evidence implicates aluminum (Al) as a risk factor for mild cognitive impairment (MCI). We hypothesized that Al-exposed workers with MCI would show altered regional homogeneity (ReHo) across large-scale cortical networks versus Al-exposed healthy controls (HCs), and that ReHo alterations would track cognitive severity. We studied 49 male workers (25 MCI, 24 HC). Resting-state fMRI data underwent standard preprocessing (discarding the first 10 volumes, slice-timing correction, realignment, normalization to MNI space, nuisance regression, and 0.01-0.10 Hz band-pass filtering). Regional homogeneity (ReHo) maps were then computed using Kendall's coefficient of concordance and subsequently smoothed with a 4-mm full-width at half-maximum (FWHM) Gaussian kernel. Group differences used independent-samples t-tests; ReHo-cognition associations used partial correlations controlling age, education, and work time; significance was FDR-controlled at q < 0.05. Cognitive performance was assessed by MoCA and RAVLT; executive function by TMT. Plasma Al concentration was measured for each participant. Compared with HCs, ReHo decreased in SMN, DAN, and VAN and increased in DMN after FDR correction, while LMN showed a nominal increase that did not survive FDR correction. Network-level ReHo showed domain-specific associations with memory and executive measures after covariate adjustment (FDR-corrected). These findings indicate network-level dysregulation of intrinsic synchrony in Al-related MCI and adverse cognitive associations of occupational Al exposure with cognition. rs-fMRI ReHo alterations within Yeo-17 networks may serve as candidate imaging biomarkers for occupational neurotoxicity-related MCI.