Effects of occupational aluminum exposure, types of alcohol consumption, and their interaction on cognitive function of workers

BackgroundOccupational aluminum exposure is closely related to cognitive impairment, and alcohol consumption is also closely related to cognitive dysfunction.ObjectiveTo explore the effects of types of alcohol consumption on cognitive function of occupational aluminum exposed workers.MethodsA total of 181 workers aged from 23 to 56 years were selected by cluster sampling method in an electrolytic aluminum workshop of an aluminum plant in a region and in a maintenance workshop of another plant in the same region from July to August, 2019. Venous blood was collected, and plasma aluminum concentration was determined by inductively coupled plasma mass spectrometry. The study subjects were divided into low and high exposure groups based on the median blood aluminum level and type of work. Their basic information was collected by occupational health examination. Workers' cognitive function was assessed using the Montreal Cognitive Assessment Scale-Beijing Edition. Logistic regression was used to analyze the association between plasma aluminum concentration and cognitive impairment, and between the types of alcohol consumption (including Baijiu, red wine, and beer) and cognitive impairment, Unconditional logistic regression was used to fit multiplicative interaction model as well as additive interaction model of plasma aluminum concentration and the types of alcohol consumption, and to calculate the relative excess relative risk due to interaction (RERI) and attributable proportion due to interaction (AP).ResultsThe M (P25, P75) concentrations of plasma aluminum were 40.01 (25.05, 60.56) µg·L−1 in the total study subjects, 25.16 (17.13, 34.78) µg·L−1 in the low exposure group and 60.56 (47.40, 68.53) µg·L−1 in the high exposure group. After adjusting the type of alcohol consumption, drinking, age, duration of exposure to aluminum, education, marital status, and smoking, the odds ratios for impairments of attention, language expression, and overall cognitive function in the high exposure group were 4.295 (95%CI: 1.912-9.648), 5.687 (95%CI: 1.355-23.867), and 2.720 (95%CI: 1.225-6.040) times of the low exposure group respectively. Besides, after adjusting blood aluminum concentration, total alcohol consumption, age, duration of exposure to aluminum, education, marital status, and smoking, the risk of attention impairment of the Baijiu drinkers was 2.613 (95%CI: 1.054 to 6.837) times of the non-Baijiu drinkers; the risks of impairment of visuospatial abilities and execution functions, language expression, delayed recall, and overall cognitive function of the beer drinkers were 3.165 (95%CI: 1.285-7.797), 17.898 (95%CI: 1.590-201.480), 3.118 (95%CI: 1.215-8.003), and 3.824 (95%CI: 1.736-8.423) times of the non-beer drinkers. There were both additive [RERI (95%CI): 1.745 (1.394-2.097), AP (95%CI): 0.415 (0.201-0.630)] and multiplicative (OR=3.591, 95%CI: 1.393-9.255) interactions between Baijiu intake and plasma aluminum concentration levels on the attention domain. The cognitive impairment attributed to the interactive effects of drinking Baijiu and plasma aluminum concentration in individuals with attention impairment accounted for 41.5%. There were both additive [RERI (95%CI): 5.955 (0.562-11.328), AP (95%CI): 0.829 (0.577-1.081)] and multiplicative (OR=42.174, 95%CI: 5.469-325.252) interactions between beer drinking and plasma aluminum concentration on the overall cognitive function. Among the individuals with overall cognitive impairment, the cognitive impairment caused by the interaction of beer drinking and plasma aluminum concentration accounted for 82.9%.ConclusionOccupation aluminum exposed workers' attention, language expression, and overall cognitive function are closely related to their plasma aluminum concentration. Plasma aluminum concentrations have interactions with Baijiu and beer consumption on cognitive impairment of workers.