Objective To explore the association between different levels of fluoride exposure and dyslipidemia in elderly people, and to analyze the influencing factors and their interactions. Methods A total of 1 143 elderly people over 60 years old were randomly selected from historical high water fluorosis areas and control areas in Tianjin. Logistic regression model and classification tree model were used to analyze the influencing factors of dyslipidemia, and to analyze the interaction between high fluoride exposure and relevant influencing factors on dyslipidemia. Results The prevalence of elevated low density lipoprotein cholesterol (LDL-C) was 5.69% (65/1 143). There was a significant difference in the prevalence of high LDL-C in different fluoride-exposed areas (2 = 0.092，P = 0.762). Multivariate logistic analysis showed that high fluoride exposure (OR=2.306，95%CI：1.185-4.491) and abdominal obesity (OR=2.274，95%CI：1.299-3.978) were risk factors for high LDL-C, while type B personality (OR=0.529，95%CI：0.308-0.908) was a protective factor for high LDL-C. The results of classification tree model showed that abdominal obesity contributed the most to the prevalence of high LDL-C in the elderly, followed by high fluoride exposure and hyperglycemia. There was a significant multiplicative interaction between high fluoride exposure and abdominal obesity on dyslipidemia (OR=5.191,95%CI：1.609-16.745，P=0.006). Conclusion High fluoride exposure may increase the risk of high LDL-C, and there is a multiplicative interaction between high fluoride exposure and abdominal obesity on dyslipidemia.

Objective: To understand the dose response relationship between urinary fluoride and dental fluorosis among children from drinking water borne endemic fluorosis areas in Tianjin, so as to provide a scientific basis for assessing fluoride exposure risk among children from endemic areas and establishing reference values for urinary fluoride. Methods: From January to December 2024, 83 endemic villages were selected in Tianjin. A total of 2 382 children aged 8-12 years from these villages underwent dental fluorosis examination, along with water fluoride and urinary fluoride testing. Additionally, data from areas where the drinking water fluorosis control target was achieved for more than 12 years (10 villages, 50 people per village) were included as controls. A restricted cubic spline model was used to analyze the relationship between urinary fluoride levels and dental fluorosis prevalence, and benchmark dose (BMD) and benchmark dose lower bound (BMDL), as well as reference dose (RfD), were calculated using the benchmark dose method. Results: The prevalence rates of dental fluorosis among children in drinking water borne endemic fluorosis areas and areas of normal fluoride content in water in Tianjin were 10.58%, 7.60%, with a geometric mean urinary fluoride level of 0.72 and 0.60 mg/L,respectively. There were statistically significant differences in both dental fluorosis prevalence and geometric mean urinary fluoride levels between the drinking water borne endemic fluorosis areas group and the areas of normal fluoride content in water ( χ 2/Z = 4.05 , -7.31, both P <0.05). Across different periods of water source improvement, there were statistically significant differences in overall population, male, and female dental fluorosis prevalence rates and geometric mean urinary fluoride levels ( χ 2/H =44.95, 23.96, 21.05; 168.39, 63.93, 107.50, all P <0.01). Significant differences were also observed across age groups among children from drinking water borne endemic fluorosis areas in terms of dental fluorosis prevalence and geometric mean urinary fluoride levels ( χ 2/H =32.14, 79.73, both P <0.01). The results of the restricted cubic spline model showed that the risk of dental fluorosis in different sex, age and overall children in the drinking water borne endemic fluorosis areas increased significantly with rising urinary fluoride concentration(all P-general trend <0.05). The BMD value for the drinking water borne endemic fluorosis areas was 1.72 mg/L, the BMDL was 1.31 mg/L, and the RfD was 1.31 mg/L. Conclusions The prevalence of dental fluorosis among children in the drinking water borne endemic fluorosis areas in Tianjin has been effectively controlled, but it is still higher than that in the areas of normal fluoride content in water. Moreover, urinary fluoride levels and dental fluorosis prevalence among children from drinking water borne endemic fluorosis areas show a clear dose response relationship.

Objective:To analyze the influencing factors of dental fluorosis of children in the drinking-water-borne endemic fluorosis (referred to as drinking-water-borne fluorosis) areas with qualified drinking water.Methods:In 2020 and 2021, the cluster sampling method was used to select the children aged 8 to 12 years old from the drinking-water-borne fluorisis areas with qualified drinking water in Tianjin City for water and urine fluoride detection, dental fluorosis examination and questionnaire survey, and logistic regression and classification tree model were used to analyze the influencing factors of dental fluorosis in children.Results:A total of 3 795 cases children aged 8 to 12 years old were investigated, and 1 001 cases of dental fluorosis were detected, and the detection rate of dental fluorosis was 26.38% (1 001/3 795). The results of logistic analysis showed that age [odds ratio ( OR) = 1.193, 95% confidence interval ( CI): 1.115 - 1.277], high urinary fluoride (1.84 - 19.40 mg/L, OR = 1.510, 95% CI: 1.169 - 1.952) and the number of permanent residents at home ≥6 ( OR = 1.377, 95% CI: 1.090 - 1.739) were risk factors of dental fluorosis in children; and the mother's with higher education level (college degree or above, OR = 0.664, 95% CI: 0.441 - 0.999), the years of water improvement ≥5 years (5 - < 10 years, OR = 0.193, 95% CI: 0.157 - 0.238; ≥10 years, OR = 0.254, 95% CI: 0.193 - 0.333) were protective factors of dental fluorosis in children. The results of classification tree model analysis showed that the years of water improvement contributed the most to the prevalence of dental fluorosis among children in the drinking-water-borne fluorisis areas with qualified drinking water, followed by age, number of permanent residents at home and urinary fluoride. The area under the receiver operating characteristic curve (AUC) of logistic regression model and classification tree model were 0.730 (95% CI: 0.711 - 0.748) and 0.721 (95% CI: 0.702 - 0.739), respectively, with good fitting effect. Conclusion:The detection rate of children's dental fluorosis in the drinking-water-borne fluorosis areas with qualified drinking water is mainly related to the years of water improvement, age, the number of permanent residents at home and urinary fluoride.

Objective:To understand the current status of overweight and obesity, the iodine nutrition level and goiter among children in Tianjin, and explore their relationships, so as to effectively adjust the prevention and control measures.Methods:From January 2019 to December 2020, one primary school was selected from all towns or streets in 16 districts of Tianjin, and non-boarding children aged 8 to 10 (age and gender balanced) were selected from each primary school. The number of children sampled in towns or streets in each district was as even as possible. Every year, 200 children from each district were investigated for height, weight, iodine of household edible salt, urinary iodine and thyroid volume. Body mass index (BMI) was calculated and its relationship with iodine nutrition level and goiter of children was analyzed.Results:A total of 6 552 children were investigated, and the median urinary iodine was 178.95 μg/L, the goiter rate was 2.15% (141/6 552). There was no significant difference in iodine content of household edible salt among children in different BMI groups ( P = 0.835), but the difference in thyroid volume was statistically significant ( P < 0.001). By constructing a restrictive cubic spline model, the risk of goiter in children of different age groups increased with increase of BMI ( P < 0.001 or P = 0.002). Conclusions:The BMI of children is closely related to thyroid volume. The influence of height and weight should be considered in diagnosis of goiter of children.

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 (χ²_trend=14.584, P<0.001; χ²_trend= 20.525, P<0.001). There were no significant differences in the prevalence and severity of dental fluorosis among children of different genders (χ²=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 (χ²_trend=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.

Objective To understand the iodine nutrition status of pregnant women in Tianjin from 2015 to 2019, and to provide a theoretical basis for pregnant women's scientific iodine supplement in the future. Methods A total of 6 939 pregnant women were randomly selected from 16 districts in Tianjin. The urine samples and home salt of the pregnant women were collected to test iodine content. Results The iodine content was determined in a total of 6 939 household salt samples of the pregnant women. The coverage rate of iodized salt was 81.78%, the consumption rate of qualified iodized salt was 66.85%, and the median salt iodine content was 25.96 mg/kg. A total of 6,938 urine samples were determined for iodine content. The median urinary iodine of the pregnant women (154.26 µg/L) reached an appropriate level of iodine nutrition, but there was an imbalance in the regional distribution (suburbs < urban areas, pregnant women in the third trimester of suburbs < pregnant women in the third trimester of urban areas, and non-elderly pregnant women in the suburbs < non-elderly pregnant women in the suburban areas). Spearman correlation analysis found that urinary iodine was positively correlated with salt iodine and the coverage rate of iodized salt (all P<0.05). The urinary iodine level in pregnant women who consumed uniodized salt was lower than the level in those who consumed qualified iodized salt (P<0.05). Conclusion The coverage rate of iodized salt and the consumption rate of qualified iodized salt in Tianjin had not yet reached the national standard for eliminating iodine deficiency disorders. Although the median urine iodine level of pregnant women generally reached an appropriate level, the level of pregnant women's urinary iodine in the suburbs was significantly lower than that in urban areas. The urinary iodine level of pregnant women in the first trimester, suburban areas (pregnant women in the first and third trimester) and pregnant women who consumed uniodized salt were still in the iodine deficiency level. Therefore, it is necessary to continue to strengthen the monitoring of pregnant women's iodine nutrition, strengthen the promotion of scientific consumption of qualified iodized salt in key populations, and provide a basis for formulating a scientific iodine supplementation policy for pregnant women.

Objective To comprehensively evaluate the health education effects of iodine deficiency disorders in different areas of Tianjin, and to provide a reference for improving the quality of iodine deficiency disorders health education. Methods The rank sum ratio method (RSR), TOPSIS and fuzzy combination were used to comprehensively evaluate the effect of health education intervention on iodine deficiency disorders in 16 areas of Tianjin. Results The evaluation results of RSR, TOPSIS and fuzzy combination method ranked N, D, and E areas in the last three places, while G, F, and P areas ranked first, second, and third. Combined with the RSR method, it was shown that in the evaluation of the effects of iodine deficiency health education interventions in 16 areas, the health education effect in G, F and P areas was classified as superior, the health education effect in D ,E and N areas was classified as inferior, and other areas were moderate. Conclusion The fuzzy combined RSR-TOPSIS method avoided the limitation of using either RSR or TOPSIS alone and made the conclusion more objective and accurate, and provided comprehensive quantitative results for the health education of iodine deficiency diseases in different areas of Tianjin. This fuzzy combination method objectively evaluated the intervention effect of health education in different areas, which provides a reference for improving the quality of health education for iodine deficiency disorders.