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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.
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Objective: To analyze correlation of occupational hydrogen fluoride exposure to low doses of bone metabolism index through occupational epidemiological investigation and benchmark dose calculation. Methods: In May 2021, using cluster sampling method, 237 workers exposed to hydrogen fluoride in a company were selected as the contact group, and 83 workers not exposed to hydrogen fluoride in an electronics production company were selected as the control group. The external exposure dose and urinary fluoride concentration, blood and urine biochemical indicators of the workers was measured.The relationship between external dose and internal dose of hydrogen fluoride was analyzed. The external dose, urinary fluoride was used as exposure biomarkers, while serum osteocalcin (BGP), serum alkaline phosphatase (AKP) and urinary hydroxyproline (HYP) were used as effect biomarkers for bone metabolism of hydrogen fluoride exposure. The benchmark dose calculation software (BMDS1.3.2) was used to calculate benchmark dose (BMD) . Results: Urine fluoride concentration in the contact group was correlated with creatinine-adjusted urine fluoride concentration (r=0.69, P=0.001). There was no significant correlation between the external dose of hydrogen fluoride and urine fluoride in the contact group (r=0.03, P=0.132). The concentrations of urine fluoride in the contact group and the control group were (0.81±0.61) and (0.45±0.14) mg/L, respectively, and the difference between the two groups was statistically significant (t=5.01, P=0.025). Using BGP, AKP and HYP as effect indexes, the urinary BMDL-05 values were 1.28, 1.47 and 1.08 mg/L, respectively. Conclusion: Urinary fluoride can sensitively reflect the changes in the effect indexes of biochemical indexes of bone metabolism. BGP and HYP can be used as early sensitive effect indexes of occupational hydrogen fluoride exposure.
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Humans , Fluorides/adverse effects , Hydrofluoric Acid , Benchmarking , Biomarkers , Occupational Exposure/adverse effectsABSTRACT
Objective To investigate the situation of drinking water fluorosis in Tianjin, to study the benchmark dose of urinary fluoride, and to provide a reference for the formulation of the standard for urinary fluoride. Methods Three fluorosis endemic areas were selected in Tianjin, and three villages in each area were selected in this study. The water fluoride was detected, and the prevalence of dental fluorosis and the urinary fluoride of children aged 8-12 years old were investigated. Results The prevalence of dental fluorosis and urinary fluoride content in children in the villages with water fluoride exceeding the standard were significantly higher than those in the villages with water fluoride qualified, and the difference was statistically significant (χ2=88.821, P＜0.001; Z=6.089, P＜0.001). The analysis of the prevalence of dental fluorosis in children showed that the younger the age, the lower the prevalence and severity of dental fluorosis (χ2trend=14.584, P2trend= 20.525, P2=0.736, P=0.391; χ2=3.649, P=0.456). There were significant differences in urinary fluoride between children with different ages and genders (H=14.768, P=0.011; Z=-2.526, P=0.012). According to the level of urinary fluoride, the children were divided into 5 groups. With the increase of urinary fluoride concentration, the prevalence of dental fluorosis gradually increased and the difference was statistically significant (χ2trend=16.348, P<0.001), showing a dose-effect relationship. Based on the prevalence of dental fluorosis in children, BMDS was used to calculate the BMD and BMDL, which were 2.20 mg/L and 1.54 mg/L, respectively. Conclusion The water reform and fluoride reduction in Tianjin has achieved certain results. There is a dose-effect relationship between urinary fluoride and prevalence of dental fluorosis in children, and the reference dose value is slightly higher than the current standard, suggesting that the current standard can be updated timely.
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Objective To explore the relationship between fluoride exposure levels and thyroid structure and function in school-age children, and to provide epidemiological evidence for the prevention and treatment of thyroid diseases and for the control of high fluoride hazards. Methods In 2019, 217 children aged 8-10 years were selected from 3 primary schools in the historical high fluoride area of Tianjin. Basic information was collected by questionnaire surveys. Urine and blood samples were collected for the determination of urine iodine, urine fluoride, and thyroid hormone as well as antibodies. The dental fluorosis was examined by Dean’s method and the thyroid structure was examined by ultrasound. Results There was no significant difference in gender, age and BMI of children with different urine fluoride levels (P>0.05). There was significant difference in the degree of dental fluorosis among children with different urine fluoride levels（χ2=16.263, P=0.012）, and the prevalence of dental fluorosis was higher in children with higher urine fluorine level. There was no significant difference in goiter, nodule, hypothyroidism, hypothyroidism and antibody double positive distribution among children with different urine fluoride levels (P>0.05), but the distribution of TGAb+ or TPOAb+ showed significant difference (χ2=8.697，P=0.034). Logistic analysis showed that there was no correlation between urinary fluoride level and antibody single positive (P>0.05). Conclusion Compared with children with low fluoride exposure levels, children with high fluoride exposure have higher antibody single positive rate, but comprehensive analysis do not find a positive correlation between urinary fluoride level and thyroid structure and disease.
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Objective To study the benchmark dose (BMD) of fluoride concentration in saliva,and to evaluate the significance of saliva fluoride on control and prevention of endemic fluorosis.Methods In September 2014,middle school students in endemic fluorosis areas and non-endemic fluorosis areas in North China Petoleum were selected as objects.The contents of fluoride in water,urine and saliva were determined.The correlation of fluoride content in water,urine fluoride and fluoride concentration in saliva was analyzed.According to the levels of the saliva fluoride concentration,the children were divided into 11 groups,＜ 1.00,1.00-,2.00-,3.00-,4.00-,5.00-,6.00-,7.00-,8.00-,9.00-and ≥ 10.00 mg/L.The prevalence of dental fluorosis and defected dental fluorosis were investigated and the saliva fluoride concentration was calculated by Banch-Mark Dose Software.Results Compared with non endemic areas,the fluoride contents in water,urine and saliva [(2.13 ± 0.13),(1.29 ±0.73),(4.01 ± 3.61) mg/L] were higher than that in endemic areas [(0.67 ± 0.13),(0.38 ± 0.08),(0.75 ± 0.12) mg/L,t =158.730,24.780,18.114,all P ＜ 0.01].The fluoride concentration in saliva was positively correlated with the fluoride content in water and urine in endemic areas (r =0.626,0.945,all P ＜ 0.01).The (BMDs and benchmark dose lower bound (BMDLs) were 0.91,0.54,3.72,3.32 mg/L respectively,calculated by Banch-Mark Dose Software.With the increase of fluoride concentration in saliva,the prevalence of dental fluorosis and defect dental fluorosis had increased too,especially when the fluoride content in saliva was more than 4 mg/L.There were significant doseresponse relationships between the urine fluoride and the prevalence of dental fluorosis and defected dental fluorosis.Conclusion The fluoride concentration in saliva could be used as one of the evaluation indexes of fluorosis,and the BMD of saliva fluoride concentration in endemic fluorosis areas is suggested as 0.91 mg/L.
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OBJECTIVES: This study aimed to confirm the efficacy of the urinary fluoride concentration/creatinine ratio for monitoring fluorine intake in fluoridated and non-fluoridated communities. METHODS: The correlations among the fluoride concentration in drinking water and that in the urine and fingernails of 52 preschool children (age, 60-72 months) from fluoridated and non-fluoridated communities were analyzed. RESULTS: The urinary fluoride concentration/creatinine ratio had a relatively high correlation with the fluoride concentration in drinking water (Pearson's correlation coefficient, 0.606; P0.05). CONCLUSIONS: The findings of this study suggest that the urinary fluoride concentration/creatinine ratio in children can be utilized as an index for monitoring excess fluoride intake in fluoridated communities.
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Child , Child, Preschool , Humans , Drinking , Drinking Water , Fluoridation , Fluorides , Fluorine , NailsABSTRACT
Hydrofluoric acid is one of the strongest irritating, corrosive and poisonous inorganic chemicals. The most significant chronic consequence of excessive fluoride exposure is the disorder of skeletal system and connective tissue. The first stage of osteofluorosis consists of an increase in the density of flatbone such as pelvic bone and vertebral bones, with coarseness and blurring of bone trabecular. Therefore we wanted to observe the change of the bone density among workers exposed to hydrofluoric acid. Questionnaires and radiological investigations were performed for 39 hydrofluoric acid manufacturing factory worker sexposed to hydrofluoric acid. And then authors checked urinary fluoride level by fluoride ion method. the radiographs were doubly read by two radiologists for reliability. The results were as follows; 1. There was a significant difference in urinary fluoride level (p0.05) among workers by the job title. 2. By the two radiologists, eight cases were read as bone fluorosis. The prevalence rate of bone fluorosis was 20.5%. 3. There was not a significant difference in general characteristic such as age, tenure and in muculoskeletal signs and symptoms between the fluorosis group and the normal group. 4. However, a close relationship between the occurence of the change of bone density and the degree of fluorde exposure such as burn was found. The difficulties in diagnosing fluorosis result from the questionable sensitively of x-ray techniques and from the non-specific associated signs and symptoms. A quantitative method such as densitometry to assessosteosclerosis and bone structure alteration and a follow-up study are needed.