Forecasting and analysis of the effect of lifestyle on cognitive dysfunction induced by occupational aluminum exposure based on Bayesian networks

OBJECTIVES

To evaluate the risk of cognitive impairment in workers with plasma aluminum concentrations and lifestyles using a Bayesian network (BN).

METHODS

In 2019, 476 male workers in the Shanxi Aluminum factory were investigated. We measured plasma aluminum concentrations in workers by inductive coupled plasma mass spectrometry (ICPMS) and tested workers' cognitive function by the MoCA scale. We collected the data of lifestyle by the occupational Workers' Health questionnaire and express the influence of lifestyle on cognition by the OR value (95 %CI) of logistic regression. A Bayesian network model was used to predict the risk of cognitive dysfunction.

RESULTS

The subjects were divided into a cognitively normal group and cognitively impaired group according to MoCA scores. There were statistically significant differences in age, education level, alcohol consumption, physical exercise, reading, aluminum length of service and blood aluminum concentration between the two groups (P < 0.05). The plasma aluminum concentration in the cognitive impairment group was 1.68 times higher than that in the cognitive normal group. Four groups were established according to the quartile of blood aluminum concentration of the subjects, namely, Group Q1 (<14.95 μg/L), Q2 group (14.95-32.96 μg/L), Q3 group (32.96-56.62 μg/L), and Q4 group (>56.62 μg/L). Binary logistic regression analysis showed that in the adjustment variable Model2, drinking, short sleep, long sleep, and mobile phone use increased the risk of cognitive impairment by 1.505(0.99,2.289), 1.269(0.702,2.295), 1.125(0.711,1.781) and 1.19(0.779,1.82), respectively, compared with their reference values. The risk of cognitive impairment from reading and exercise was 0.7(0.398,1.232) and 0.787(0.51,1.217), respectively, compared with those of no reading and no exercise. The risk of cognitive impairment of blood aluminum concentration in the Q2, Q3, and Q4 groups was 2.103(1.092,4.051), 1.866(0.955,3.644) and 3.679(1.928,7.020), respectively, compared with that in the Q1 group. Compared with age <40 , the risk of cognitive impairment of age ≥40 was 2.515(1.508,4.193) (P < 0.05). Bayesian network model results showed that if all participants had plasma aluminum concentrations higher than Q4, the prevalence of cognitive impairment was 54.5 %. The prevalence of cognitive impairment was 75.0 % if all participants had plasma aluminum levels above Q4, were older than 40, smoked, drank alcohol, used a cell phone for more than 2 h, slept for more than 8 h, did not exercise, and did not read.

CONCLUSIONS

Our findings suggest that both poor lifestyle and occupational aluminum exposure may affect cognitive function. Workers must maintain a reasonable lifestyle and reduce aluminum exposure, which can control the occurrence of cognitive impairment.

Blood glucose mediated the effects of cognitive function impairment related to aluminum exposure in Chinese aluminum smelting workers

OBJECT

To explore the effects of occupational aluminum exposure on workers' cognitive function and blood glucose concentration, and to analyze whether blood glucose concentration can mediate the cognitive changes caused by aluminum.

METHOD

Our study recruited 375 workers from an aluminum factory in northern China. We collected the fasting elbow venous blood of the workers, measured their fasting blood glucose concentration (FBG), and used ICP-MS to determine plasma aluminum concentration (P-Al) as an indicator of internal exposure. The Montreal Cognitive Assessment (MoCA), was used to assess the cognitive function of workers. Generalized linear model was used to analyze the association of P-Al with cognitive function and blood glucose concentration, and the restricted cubic spline model was used to fit the dose-response relationship. We also conducted a mediation effect analysis.

RESULT

We observed the dose-response relationship, that is, as the P-Al increased, sum of MoCA, visuospatial/executive, naming, language, and abstraction scores decreased, and the blood glucose concentration increased. For every e-fold increase in P-Al, sum of MoCA, visuospatial/executive, naming, language, and abstraction scores decreased by 0.328 points, 0.120 points, 0.059 points, 0.060 points, and 0.083 points, respectively, and FBG rose by 0.109 mmol/L. FBG has a significant mediating effect between P-Al and sum of MoCA (P for mediator=0.042), and it could explain 10.7% of the effect of cognitive level related to P-Al.

CONCLUSION

Occupational aluminum exposure negatively affected the cognitive function of workers and positively affected FBG. FBG may partially explain the impact of occupational aluminum exposure on workers' cognitive function.

Aluminum-Induced Cognitive Impairment and PI3K/Akt/mTOR Signaling Pathway Involvement in Occupational Aluminum Workers

Epidemiological studies indicate that long-term occupational exposure to aluminum (Al) causes neurotoxicity and cognitive impairment. While the molecular underpinnings associated with workers' cognitive impairment is unclear, one mechanism may involve Al-induced PI3K/Akt/mTOR activation and neuronal cell death, which impairs learning and memory in rats. Here, we sought to determine whether PI3K/Akt/mTOR is also associated with cognitive impairment in Al-exposed occupational workers. Cognitive function was screened by Mini-Mental State Examination (MMSE) and Clock-Drawing Test (CDT), and serum Al and PI3K/Akt/mTOR-associated gene expression was quantified. A negative correlation between serum Al and scores of MMSE and CDT was found, which might relate with downregulation of PI3K/Akt/mTOR. To determine the role of the PI3K/Akt/mTOR pathway cognitive function, we treated zebrafish with Al and observed a profound impairment in learning and memory. Increased brain Al levels was associated with decreased expression of PI3K/Akt/mTOR in Al-exposed zebrafish. Finally, rapamycin, an mTOR inhibitor, was added to isolate the role of mTOR specifically in the Al exposed zebrafish. The results suggested that Al induces learning and memory deficits by downregulating PI3K, Akt, and mTOR1 expression and inducing neuronal cell death like rapamycin group. This study indicates that aluminum exposure can cause cognitive impairment through PI3K/Akt/mTOR pathway, with mTOR activity being a critical player involved in this mechanism. Future studies are necessary to further characterize the role of PI3K/Akt/mTOR1 signaling in Al-induced neurocognitive decline among Al occupational workers. These findings draw attention to Al risk exposure among occupational workers and the need to implement novel safety and protective measures to mitigate neurocognitive health risks in the Al industrial workspace.