A Bayesian network for estimating hypertension risk due to occupational aluminum exposure.

Background: The correlation between metals and hypertension, such as sodium, zinc, potassium, and magnesium, has been confirmed, while the relationship between aluminum and hypertension is not very clear. This study aimed to evaluate the correlation between plasma aluminum and hypertension in electrolytic aluminum workers by the Bayesian networks (BN). Methods: In 2019, 476 male workers in an aluminum factory were investigated. The plasma aluminum concentration of workers was measured by inductively coupled plasma mass spectrometry. The influencing factors on the prevalence of hypertension were analyzed by the BN. Results: The prevalence of hypertension was 23.9% in 476 male workers. The risk of hypertension from plasma aluminum in the Q2, Q3, and Q4 groups was 5.20 (1.90-14.25), 6.92 (2.51-19.08), and 7.33 (2.69-20.01), respectively, compared with that in the Q1 group. The risk of hypertension from the duration of exposure to aluminum of >10 years was 2.23 (1.09-4.57), compared without aluminum exposure. Area under the curve was 0.80 of plasma aluminum and the duration of exposure to aluminum was based on covariates, indicating that aluminum exposure had important predictive value in the prevalence of hypertension in the occupational population. The results of the study using the BN model showed that if the plasma aluminum of all participants was higher than Q4 (≥47.86 µg/L) and the participants were drinking, smoking, diabetes, central obesity, dyslipidemia, and aged >50 years, the proportion of hypertension was 71.2%. Conclusions: The prevalence of hypertension increased significantly with the increase of plasma aluminum level.

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 pressure mediated the effects of cognitive function impairment related to aluminum exposure in Chinese aluminum smelting workers.

OBJECTIVES: The aim of this study is to investigate the effects that the Al on blood pressure and the effect of hypertension in aluminum-induced cognitive impairment in electrolytic aluminum worker. METHODS: The study was conducted 392 male aluminum electrolytic workers in an aluminum plant of China. The concentration of alumina dust in the air of the electrolytic aluminum workshop is 1.07 mg/m3-2.13 mg/m3. According to the Permissible concentration-Time Weighted Average of alumina dust is 4 mg/m3, which does not exceed the standard. The blood pressure of the workers was measured. The plasma aluminum concentration of workers was determined by ICP-MS (Inductively Coupled Plasma Mass Spectrometry). Cognitive functions were measured using MMSE (Mini-Mental State Examination), VFT (Verbal Fluency Test), ATIME (Average Reaction Time), FOM (Fuld Object Memory Evaluation), DST (Digit Span Test), CDT (Clock Drawing Test) scales. Modified Poisson regression was used to analyze the risk of hypertension and cognitive impairment with different plasma aluminum concentrations. Generalized linear regression model was used to analyze the relationship between aluminum and cognitive function, blood pressure and cognitive function. Causal Mediation Analysis was used to analyze the mediation effect of blood press in aluminum-induced cognitive impairment. RESULTS: Plasma aluminum appeared to be a risk factor for hypertension (PR (prevalence ratio) = 1.630, 95 %-CI (confidence interval): 1.103-2.407), systolic blood pressure (PR = 1.578, 95 %-CI: 1.038-2.399) and diastolic blood pressure (PR = 1.842, 95 %-CI: 1.153-2.944). And plasma aluminum increased by e-fold, the scores of MMSE and VFT decreased by 0.630 and 2.231 units respectively and the time of ATIME increased by 0.029 units. In addition, generalized linear regression model showed that blood press was negatively correlated with the scores of MMSE and VFT. Finally, causal Mediation Analysis showed that hypertension was a part of the mediating factors of aluminum-induced decline in MMSE score, and the mediating effects was 16.300 % (7.100 %, 33.200 %). In addition, hypertension was a part of the mediating factors of aluminum-induced decline in VFT score, and the mediating effects was 9.400 % (2.600 %, 29.000 %) CONCLUSION: Occupational aluminum exposure increases the risk of hypertension and cognitive impairment. And hypertension may be a mediating factor of cognitive impairment caused by aluminum exposure.

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.

Mechanism by Which Aluminum Regulates the Abnormal Phosphorylation of the Tau Protein in Different Cell Lines.

Aluminum (Al) is an environmental neurotoxin to which humans are extensively exposed; however, the molecular mechanism of aluminum toxicity is unclear. Several studies have indicated that exposure to aluminum can cause abnormal phosphorylation of the tau protein. The purpose of this study was to investigate respectively the special molecular mechanism of abnormal regulation on synthesis and degradation of the tau protein induced by AlCl3 in cells of different species. The results of tau protein showed that the sites of abnormal tau phosphorylation induced by AlCl3 are Thr231, Ser262, and Ser396 in N2a cells. Meanwhile, the expressions of Thr181, Thr231, and Ser262 increased abnormally in SH-SY5Y cells. The result of the study showed that PP2A expression was high in N2a cells, while GSK-3ß and PP2A in SH-SY5Y cells were involved in the synthesis process of abnormal tau phosphorylation induced by AlCl3. In N2a cells, the ubiquitin-proteasome pathway (UPP) mainly regulated tau phosphorylation at Ser262 and Ser396. Meanwhile, in SH-SY5Y cells, the UPP mainly regulated tau phosphorylation at Thr231 and Ser396. In summary, the UPP is involved in the degradation of Tau that is abnormally phosphorylated induced by AlCl3, but this process is site-specific and differs in cells of different species.