Neurotoxic Effects of Aluminium Among Foundry Workers and Alzheimer’s Disease

• Published in: Neurotoxicology (Park Forest South) Vol. 23; no. 6; pp. 761 - 774
• Main Authors: Polizzi, Salvatore, Pira, Enrico, Ferrara, Mauro, Bugiani, Massimiliano, Papaleo, Andrea, Albera, Roberto, Palmi, Silvana
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2002
• Subjects: Aged; Aluminium; Aluminum - blood; Aluminum - toxicity; Alzheimer Disease - blood; Alzheimer Disease - chemically induced; Alzheimer Disease - epidemiology; Alzheimer’s disease; Case-Control Studies; Clock Drawing Test (CDT); Cognition - drug effects; Cognition - physiology; Cognition Disorders - blood; Cognition Disorders - chemically induced; Cognition Disorders - epidemiology; Cross-Sectional Studies; Endogenous Event-Related Potential (ERP-P300); Humans; Linear Models; Metallurgy; Middle Aged; Mini Mental State Examination (MMSE); Neuropsychological Tests - statistics & numerical data; Neurotoxicity; Occupational Exposure - adverse effects; Occupational Exposure - statistics & numerical data; Neurotoxicity; Clock Drawing Test (CDT); Aluminium; Alzheimer’s disease; Mini Mental State Examination (MMSE); Endogenous Event-Related Potential (ERP-P300)
• ISSN: 0161-813X; 1872-9711
• DOI: 10.1016/S0161-813X(02)00097-9

Background : In a cross-sectional case-control study conducted in northern Italy, 64 former aluminium dust-exposed workers were compared with 32 unexposed controls from other companies matched for age, professional training, economic status, educational and clinical features. The findings lead the authors to suggest a possible role of the inhalation of aluminium dust in pre-clinical mild cognitive disorder which might prelude Alzheimer’s disease (AD) or AD-like neurological deterioration. Methods : The investigation involved a standardised occupational and medical history with particular attention to exposure and symptoms, assessments of neurotoxic metals in serum: aluminium (Al-s), copper (Cu-s) and zinc (Zn-s), and in blood: manganese (Mn-b), lead (Pb-b) and iron (Fe-b). Cognitive functions were assessed by the Mini Mental State Examination (MMSE), the Clock Drawing Test (CDT) and auditory evoked Event-Related Potential (ERP-P300). To detect early signs of mild cognitive impairment (MCI), the time required to solve the MMSE (MMSE-time) and CDT (CDT-time) was also measured. Results : Significantly higher internal doses of Al-s and Fe-b were found in the ex-employees compared to the control group. The neuropsychological tests showed a significant difference in the latency of P300, MMSE score, MMSE-time, CDT score and CDT-time between the exposed and the control population. P300 latency was found to correlate positively with Al-s and MMSE-time. Al-s has significant effects on all tests: a negative relationship was observed between internal Al concentrations, MMSE score and CDT score; a positive relationship was found between internal Al concentrations, MMSE-time and CDT-time. All the potential confounders such as age, height, weight, blood pressure, schooling years, alcohol, coffee consumption and smoking habit were taken into account. Conclusions : These findings suggest a role of aluminium in early neurotoxic effects that can be detected at a pre-clinical stage by P300, MMSE, MMSE-time, CDT-time and CDT score, considering a 10 μg/l cut-off level of serum aluminium, in aluminium foundry workers with concomitant high blood levels of iron. The authors raise the question whether pre-clinical detection of aluminium neurotoxicity and consequent early treatment might help to prevent or retard the onset of AD or AD-like pathologies.