Objective To describe the changes in cognitive function of an occupational population with exposure to aluminum, screen for mild cognitive impairment (MCI) patients, and probe into the subtype distributions.
Methods Workers occupationally exposed to aluminum (n=172) including electrolysis and mining workers from an aluminum plant were enrolled to the present study. Questionnaires consisted of mini mental state examination (MMSE), clock drawing test (CDT), digit span (DS), fuld object memory (FOM), and rapid verbal retrieve (RVR), and were distributed to the workers for cognitive function evaluation. Graphite furnace atomic absorption spectrometry was used to detect blood aluminum content.
Results A high n=70, (72.45& #177;9.25)μg/L and a low n=102, (19.90& #177;10.65)μg/L blood aluminum groups were divided by the mean level of blood aluminum (41.86 μg/L) of all workers' samples. The high blood aluminum group significantly scored higher in MMSE, CDT, DS, FOM, and RVR tests than the low blood aluminum group (P<0.05). The high blood aluminum group also reported a higher MCI detection rate (28.6%) than the low blood aluminum group (14.7%) (P<0.05). In this regard, the number of workers with amnestic mild cognitive impairment (aMCI) was 18 cases versus 8 cases in the high and the low blood aluminum groups respectively, and the aMCI/MCI ratio was also statistically higher in the high blood aluminum group than in the low group (90.0% versus 53.3%)(P<0.05). The results of logistic regression analysis showed that the main influencing factors leading to aMCI included age, length of exposure, and aluminum content in blood.
Conclusion Long-term occupational exposure to aluminum is a risk factor for MCI, and aMCI is the predominant subtype.
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