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Background Aluminum and fluoride are neurotoxic, and aluminum exposure alone is closely related to the overall cognitive function of operational workers. It is unclear about the effect of aluminum and fluoride interactions on cognitive function. Objective To evaluate a potential interaction effect of blood aluminum and urinary fluoride on the overall cognitive function of workers working in an aluminum plant. Methods Using cluster sampling, 230 workers in the electrolysis workshop of an aluminum group company in Shanxi Province were selected, and plasma aluminum concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS) and urinary fluoride by ion-selective electrode. The study participants were divided into a low blood aluminum group and a high blood aluminum group according to the median (M) of blood aluminum concentration, and a low urinary fluoride group and a high urinary fluoride group by a predetermined cutoff point (2.160 mg·L−1). The Montreal Cognitive Assessment-Beijing (MoCA-BJ) was used to assess overall cognitive function of the workers. Logistic regression model was used to analyze the relationship between blood aluminum, urinary fluoride, and mild cognitive impairment (MCI), including multiplicative interaction analysis and correlation analysis; R language was used to fit an additive interaction model of blood aluminum and urinary fluoride on MCI and to calculate synergy index (S), relative excess risk due to interaction (RERI), and attributable proportion due to interaction (API). Results Among the 230 operational workers, the median blood aluminum concentration (P25, P75) was 40.11 (25.16, 58.89) µg·L−1, and there were 104 cases of abnormal urinary fluoride, with an abnormality rate of 45.2%. There was a multiplicative interaction (OR=7.783, 95%CI: 1.377, 43.991) and no additive interaction (RERI=0.030, 95%CI: −0.498, 0.559; API=0.018, 95%CI: −0.279, 0.316; S=1.049, 95%CI: 0.519, 2.118) for the effect between blood aluminum and urinary fluoride on overall cognitive function of the workers. The logistic regression analysis showed that the risk of MCI was 12.105 (95%CI: 2.802, 52.287) times higher in workers with both high blood aluminum and high urinary fluoride than in those with low blood aluminum and low urinary fluoride, after adjusting for selected influencing factors. Conclusion Occupational exposure related high blood aluminum and high urinary fluoride are risk factors for cognitive dysfunction, and the coexistence of both indicators increases the risk of MCI in workers with occupational aluminum exposure, with a multiplicative interaction.
ABSTRACT
Per- and polyfluoroalkyl substances (PFASs) are persistent organic pollutants (POPs). They are widely used in food packaging, tableware coating, stain resistant furniture, and other industrial production. Humans are exposed to PFASs on a daily basis through drinking water and intaking food, use of consumer products containing PFASs, and occupational exposure during the production of PFASs or related products. A growing body of toxicological studies has shown that PFASs exposure disrupts the thyroid hormone (TH) system and causes hypothyroidism, which is further supported by population epidemiological studies. PFASs can damage thyroid follicular cells and sodium/iodine transporters to impair iodine uptake by thyroid cells. They interfere with the synthesis of thyroglobulin, reduce the activity of thyroid peroxidase, and affect the synthesis and secretion of TH. They interfere with TH transportation and biological effects via TH competitive binding thyroid transporter or thyroid hormone receptor. They suppress TH signaling pathway and deiodinase activity, interfere negative feedback mechanism, and accelerate TH metabolism and excretion. The processes of TH synthesis, transport, degradation, and biological effects may all be affected by PFASs exposure. This paper described possible toxic mechanisms of PFASs on the thyroid from four aspects: TH biosynthesis, transport, action on target cells, and metabolic excretion stage, and summarized the thyroid toxicity associated with PFASs exposure.
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Objective@#To examine the correlation between visuospatial construction ability and occupational aluminum exposure among aluminum workers, so as to provide the evidence for early protection of occupational injury among aluminum workers.@*Methods@#A total of 442 workers in an aluminum factory in Shanxi Province were selected using a cluster sampling method, and participants' demographic features and occupational history were collected. The blood aluminum concentration was measured using inductively coupled plasma mass spectrometry (ICP-MS), and the visuospatial construction ability was evaluated with the Cube Copying Test (CCT) of the Chinese version of the Montreal Cognitive Assessment (MoCA). The correlation between the visuospatial construction ability and blood aluminum concentration was examined using a multivariable logistic regression model.@*Results@#A total of 442 aluminum workers were enrolled, and all participants were male, with a mean age of (43.40±7.31) years, labor service duration of (23.64±8.35) years and a mean blood aluminum concentration of 33.87 µg/L. Of all participants, there were 206 workers with impaired visuospatial construction ability (46.61%), including 127 workers with blood aluminum concentrations of >33.87 µg/L (61.65%); 190 workers with educational duration of 6 to 9 years (92.23%), 118 electrolytic aluminum workers (57.28%), 114 workers with work shifts (55.34%), and 123 workers with a very good sleep quality (59.71%). Multivariable logistic regression analysis revealed that blood aluminum concentrations of >33.87 µg/L (OR=2.490, 95%CI: 1.531-4.052), educational duration of 6 years or more (OR: 0.075-0.246, 95%CI: 0.015-0.622), work type as a non-electrolytic aluminum worker (OR=0.838, 95%CI: 0.425-0.987), work shift (OR=1.179, 95%CI: 1.078-1.435) and a very good sleep quality (OR=0.104, 95%CI: 0.012-0.896) significantly correlated with impaired visuospatial construction ability among aluminum worker.@*Conclusion@#Impaired visuospatial construction ability correlates with occupational aluminum exposure among aluminum workers.
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Objective To analyze current situation and problems of health manager training in the pilot training areas. Method With the recommendations of health administration deputies in the plot areas of Shanghai, Chongqing and Urumqi, 2 centers for community health services (CHSs) were selected in each area, 9 relative persons were interviewed, 3 focus group discussions (FGDs) involved 18 persons were held totally. The FGDs focused on such questions as“the general information of the training students”“the objectives and purposes of the training in each area”, and so on. Field investigation and qualitative analysis were used to investigate the status quo and main problems of the training of health manager in the pilot areas. Result The problems of the training of health manager existing in the pilot areas mainly are:part of teachers were not fully competent to the training of health manager, training of operant skill was insufficient, training course was not unified, the assessment mechanism was not perfect. Conclusion Optimizing the construction of teachers team, standardizing the training content, increasing the time of operating skills training, establishing a unified and standardized assessment mechanism are essential.