171. 李晓松,姚仲英,邹亚丁,等.碘干预对燃煤氟中毒地区儿童甲状腺影响的研究[J].中国预防医学杂志,2007,(3):227-228
http://new.med.wanfangdata.com.cn/Paper ... z200703017
Li XS, Yao ZY, Zou YD, Chen CQ, Chen J - "Effects of iodine intervention on thyroid gland of children in coal-burning fluorosis area" China Preventive Medicine 8(03):227-228 (2007)
目的 了解食盐加碘以来贵州燃煤氟中毒病区儿童碘缺乏病情指标的变化.方法 采用现场流行病学抽样调查方法,对贵州氟中毒重病区织金县八步乡儿童进行尿碘水平及甲状腺肿大率调查,并与历史本底资料对比.结果 被调查的氟病区儿童尿碘中位数为338.7μg/L,高于补碘前3倍,66.70%的儿童尿碘水平高于300μg/L,超过WHO推荐的100～200μg的日摄入量;7～14岁儿童青少年甲状腺肿大率7.1%,是补碘前(0.3%)的23.7倍.结论 贵州有37个燃煤型氟中毒病区县,病区人口1 900余万,历史上是碘缺乏病的轻病区,八步乡儿童青少年甲状腺肿大率上升的原因有待进一步研究.
2007 - I intervention - children- DF and goiter in fluorosis
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Re: 2007 - I intervention - children- DF and goiter in fluorosis
Title: Research on the Effects of Iodine Intervention on the Thyroid Gland of Children in Coal-burning Fluorosis Areas
Published in: Chinese Journal of Preventive Medicine, June 2007, Volume 8, Issue 3
Authors: Li Xiaosong, Yao Zhongying, Zou Yading, Chen Shiqing, Chen Jian
Abstract:
Objective: To understand the changes in iodine deficiency disorder (IDD) indicators among children in coal-burning fluorosis areas in Guizhou since the implementation of iodized salt.
Methods: A field epidemiological sampling survey was conducted to investigate urinary iodine levels and the prevalence of goiter among children in a severe fluorosis area, Babu Township, Zhijin County, Guizhou, and compared with historical baseline data.
Results: The median urinary iodine level of children in the fluorosis area was 338.7 µg/L, three times higher than before iodization, with 66.70% of children having urinary iodine levels above 300 µg/L, exceeding the WHO-recommended daily intake of 100-200 µg. The goiter rate among 7-14-year-old children was 7.1%, 23.7 times higher than before iodization (0.3%).
Conclusion: Guizhou has 37 counties with coal-burning fluorosis, with a population of over 1.3 million. Historically, these areas were mild iodine-deficiency areas. The reasons for the rise in goiter rate among children in Babu Township require further study.
Keywords: Iodine intervention, Coal-burning fluorosis, Children, Goiter
Introduction:
Guizhou Province has two major endemic diseases: coal-burning fluorosis and iodine deficiency disorders (IDD). The distribution of endemic diseases in Guizhou is clearly demarcated. The northwest, where coal is the primary fuel, is a fluorosis area, while the southeast, where wood is the main fuel, suffers from severe iodine deficiency. Historically, no area in Guizhou has reported the simultaneous occurrence of both fluorosis and IDD. Early sampling surveys from the 1980s indicated that the goiter rate among 7-14-year-old students in the northwest fluorosis areas was only 0.3%-2%, with no cases of cretinism.
In order to understand the changes in IDD indicators among children and adolescents in fluorosis areas since the implementation of iodine intervention, the authors conducted a survey of 7-14-year-old children in Babu Township, Zhijin County, Guizhou from September to November 2005. The results are as follows.
1. Subjects and Methods
1.1 Background Information:
Babu Township, located in northwest Guizhou, primarily uses coal as fuel, with the practice of open-fire coal cooking, heating, and grain drying. The 1983 (pre-iodization) survey indicated that the prevalence of dental fluorosis among 7-14-year-old students was 99.6%, categorizing the area as a severe fluorosis zone. The local reservoir water had an iodine content of 21.5 µg/L (during the wet season), and the goiter rate was 0.3%. The geometric mean urinary iodine was 111.90 ± 58.12 µg/g creatinine, classifying the area as a mild IDD zone.
1.2 Study Population:
1.2.1 Examination of thyroid glands was conducted on all 339 students aged 7-14 at the central school of Babu Township. To ensure reliability, the examiners were the same individuals who participated in the baseline survey in 1983, and two people had to confirm the diagnosis. Dental fluorosis was also examined in the 339 students.
1.2.2 A random sample of 72 students from the 7-14 age group (10 per age group, half male and half female) was selected from the 339 students. A 30 ml urine sample was collected for each student to measure urinary iodine and fluoride levels.
1.3 Methods:
1.3.1 Dental Fluorosis Rate: Detected using the Dean method.
1.3.2 Urinary Iodine and Fluoride: Measured using the acid digestion arsenic-cerium oxidation method and fluoride ion-selective electrode method, respectively.
2. Results
2.1 Goiter Rate:
Among the 339 students aged 7-14, 24 students were found to have grade 1 goiter, with a goiter rate of 7.1%. This was a statistically significant increase compared to the 1983 survey (0.3%), with χ² = 3.864, P < 0.01.
2.2 Dental Fluorosis Detection Rate:
Of the 339 students examined, 248 were found to have dental fluorosis, with a prevalence rate of 73.2%.
2.3 Urinary Fluoride Levels:
The geometric mean urinary fluoride level among the 72 students aged 7-14 was 2.51 mg/L. The results of dental fluorosis detection and urinary fluoride levels indicate that Babu Township in Zhijin County remains a severe fluorosis area.
2.4 Urinary Iodine Levels:
The median urinary iodine level was 338.7 µg/L. Frequency distribution: 57 students (79.2%) had urinary iodine levels >300 µg/L; 12 students (16.7%) had levels >400 µg/L; 6 students (8.3%) had levels >500 µg/L; and 9 students (12.5%) had levels ≥600 µg/L. The urinary iodine levels of the children were three times higher than in 1983 (111.90 ± 58.12 µg/g creatinine). The frequency distribution indicates that most children and adolescents are consuming far more iodine than the WHO-recommended daily intake of 100-200 µg.
3. Discussion
The impact of fluoride and iodine on the prevalence of goiter is inconsistent in various reports. Most animal experiments and epidemiological studies suggest that excessive fluoride can cause or promote the prevalence of goiter, regardless of iodine deficiency or sufficiency. Theoretically, fluoride is more chemically active than iodine among halogens, competing with iodine and affecting its uptake and concentration by the thyroid gland. However, the 1983 survey in Babu Township, Zhijin County, showed a dental fluorosis rate of 99.6% among students, while the goiter rate was only 0.3%. This result does not support the aforementioned theory. The 2005 survey showed a decrease in the dental fluorosis rate, but a significant increase in the goiter rate, suggesting that the increase in goiter rate was not caused by fluoride. The discrepancy with other reports may be due to differences in the causative agents and pathways between waterborne fluorosis and coal-burning fluorosis.
Iodine and fluoride are elements of the same group and have parallel distribution in the environment. Some data suggest that the volcanic areas in western Guizhou, where coal formation occurred during volcanic eruptions, have high iodine content in the coal. This might have supplemented the iodine deficiency in the external environment. The iodine content in local coal, reported to be as high as 6.94 mg/kg, and the iodine concentration in water (21.5 µg/L) seem to support this. Additionally, it has been reported that corn and chili peppers dried over coal-burning stoves in fluorosis areas saw a 3-8 fold increase in iodine content after three months of drying. The indoor air iodine concentration in coal-burning households was 40 times higher than outdoor air. This might explain why iodine deficiency was not observed among children in Babu Township before the implementation of iodized salt, as their iodine intake was likely supplemented by food and air rich in iodine.
The frequency distribution of urinary iodine levels shows that 79.2% of children and adolescents in Babu Township have urinary iodine levels exceeding 300 µg/L, indicating that most of the children are consuming more iodine than recommended by WHO. Although the human body has a high tolerance for iodine, individual iodine metabolism and the body's response to excessive iodine vary. The rising goiter rate in Babu Township children may be related to long-term excessive iodine intake, disrupting the original iodine balance in the population. Further research is needed to understand this issue.
Conclusion: Babu Township in Zhijin County represents only a part of the coal-burning fluorosis areas in Guizhou, where 37 counties are affected by fluorosis. Historically, these areas were mild or non-IDD regions. Whether other areas might experience similar conditions as Babu Township should be closely monitored.
References:
WHO/UNICEF/ICCIDD. Assessment of iodine deficiency disorders and monitoring their elimination: a guide for program managers. WHO, 2001.
Zhao Wenyuan, Zhu Huimin, Gao Youzhen, et al. Study on the combined effects of high iodine and high fluoride on experimental thyroid and fluorosis. Hebei Medical Journal, 1989, 10:69-72.
Xu Baoquan. Experimental study on the impact of chronic fluorosis on the thyroid gland. Journal of Clinical and Experimental Pathology, 1990, 6:4.
Yu Yanni, Dong Zhong, Liu Jialiu. Stereological parameters of the thyroid gland in fetuses from fluorosis areas in Guizhou. Chinese Journal of Endemiology, 1998, 13:148.
Li Xianji. Geological and epidemiological prediction of fluorosis endemic areas in Guizhou. Geological Geochemistry, 1982, 12:89-92.
Duan Rongxiang, Li Ping, An Dong, et al. Relationship between coal-burning and endemic goiter in Guizhou. Environmental Geochemistry and Health, Beijing: Seismological Press, 1987, 8-10.
Published in: Chinese Journal of Preventive Medicine, June 2007, Volume 8, Issue 3
Authors: Li Xiaosong, Yao Zhongying, Zou Yading, Chen Shiqing, Chen Jian
Abstract:
Objective: To understand the changes in iodine deficiency disorder (IDD) indicators among children in coal-burning fluorosis areas in Guizhou since the implementation of iodized salt.
Methods: A field epidemiological sampling survey was conducted to investigate urinary iodine levels and the prevalence of goiter among children in a severe fluorosis area, Babu Township, Zhijin County, Guizhou, and compared with historical baseline data.
Results: The median urinary iodine level of children in the fluorosis area was 338.7 µg/L, three times higher than before iodization, with 66.70% of children having urinary iodine levels above 300 µg/L, exceeding the WHO-recommended daily intake of 100-200 µg. The goiter rate among 7-14-year-old children was 7.1%, 23.7 times higher than before iodization (0.3%).
Conclusion: Guizhou has 37 counties with coal-burning fluorosis, with a population of over 1.3 million. Historically, these areas were mild iodine-deficiency areas. The reasons for the rise in goiter rate among children in Babu Township require further study.
Keywords: Iodine intervention, Coal-burning fluorosis, Children, Goiter
Introduction:
Guizhou Province has two major endemic diseases: coal-burning fluorosis and iodine deficiency disorders (IDD). The distribution of endemic diseases in Guizhou is clearly demarcated. The northwest, where coal is the primary fuel, is a fluorosis area, while the southeast, where wood is the main fuel, suffers from severe iodine deficiency. Historically, no area in Guizhou has reported the simultaneous occurrence of both fluorosis and IDD. Early sampling surveys from the 1980s indicated that the goiter rate among 7-14-year-old students in the northwest fluorosis areas was only 0.3%-2%, with no cases of cretinism.
In order to understand the changes in IDD indicators among children and adolescents in fluorosis areas since the implementation of iodine intervention, the authors conducted a survey of 7-14-year-old children in Babu Township, Zhijin County, Guizhou from September to November 2005. The results are as follows.
1. Subjects and Methods
1.1 Background Information:
Babu Township, located in northwest Guizhou, primarily uses coal as fuel, with the practice of open-fire coal cooking, heating, and grain drying. The 1983 (pre-iodization) survey indicated that the prevalence of dental fluorosis among 7-14-year-old students was 99.6%, categorizing the area as a severe fluorosis zone. The local reservoir water had an iodine content of 21.5 µg/L (during the wet season), and the goiter rate was 0.3%. The geometric mean urinary iodine was 111.90 ± 58.12 µg/g creatinine, classifying the area as a mild IDD zone.
1.2 Study Population:
1.2.1 Examination of thyroid glands was conducted on all 339 students aged 7-14 at the central school of Babu Township. To ensure reliability, the examiners were the same individuals who participated in the baseline survey in 1983, and two people had to confirm the diagnosis. Dental fluorosis was also examined in the 339 students.
1.2.2 A random sample of 72 students from the 7-14 age group (10 per age group, half male and half female) was selected from the 339 students. A 30 ml urine sample was collected for each student to measure urinary iodine and fluoride levels.
1.3 Methods:
1.3.1 Dental Fluorosis Rate: Detected using the Dean method.
1.3.2 Urinary Iodine and Fluoride: Measured using the acid digestion arsenic-cerium oxidation method and fluoride ion-selective electrode method, respectively.
2. Results
2.1 Goiter Rate:
Among the 339 students aged 7-14, 24 students were found to have grade 1 goiter, with a goiter rate of 7.1%. This was a statistically significant increase compared to the 1983 survey (0.3%), with χ² = 3.864, P < 0.01.
2.2 Dental Fluorosis Detection Rate:
Of the 339 students examined, 248 were found to have dental fluorosis, with a prevalence rate of 73.2%.
2.3 Urinary Fluoride Levels:
The geometric mean urinary fluoride level among the 72 students aged 7-14 was 2.51 mg/L. The results of dental fluorosis detection and urinary fluoride levels indicate that Babu Township in Zhijin County remains a severe fluorosis area.
2.4 Urinary Iodine Levels:
The median urinary iodine level was 338.7 µg/L. Frequency distribution: 57 students (79.2%) had urinary iodine levels >300 µg/L; 12 students (16.7%) had levels >400 µg/L; 6 students (8.3%) had levels >500 µg/L; and 9 students (12.5%) had levels ≥600 µg/L. The urinary iodine levels of the children were three times higher than in 1983 (111.90 ± 58.12 µg/g creatinine). The frequency distribution indicates that most children and adolescents are consuming far more iodine than the WHO-recommended daily intake of 100-200 µg.
3. Discussion
The impact of fluoride and iodine on the prevalence of goiter is inconsistent in various reports. Most animal experiments and epidemiological studies suggest that excessive fluoride can cause or promote the prevalence of goiter, regardless of iodine deficiency or sufficiency. Theoretically, fluoride is more chemically active than iodine among halogens, competing with iodine and affecting its uptake and concentration by the thyroid gland. However, the 1983 survey in Babu Township, Zhijin County, showed a dental fluorosis rate of 99.6% among students, while the goiter rate was only 0.3%. This result does not support the aforementioned theory. The 2005 survey showed a decrease in the dental fluorosis rate, but a significant increase in the goiter rate, suggesting that the increase in goiter rate was not caused by fluoride. The discrepancy with other reports may be due to differences in the causative agents and pathways between waterborne fluorosis and coal-burning fluorosis.
Iodine and fluoride are elements of the same group and have parallel distribution in the environment. Some data suggest that the volcanic areas in western Guizhou, where coal formation occurred during volcanic eruptions, have high iodine content in the coal. This might have supplemented the iodine deficiency in the external environment. The iodine content in local coal, reported to be as high as 6.94 mg/kg, and the iodine concentration in water (21.5 µg/L) seem to support this. Additionally, it has been reported that corn and chili peppers dried over coal-burning stoves in fluorosis areas saw a 3-8 fold increase in iodine content after three months of drying. The indoor air iodine concentration in coal-burning households was 40 times higher than outdoor air. This might explain why iodine deficiency was not observed among children in Babu Township before the implementation of iodized salt, as their iodine intake was likely supplemented by food and air rich in iodine.
The frequency distribution of urinary iodine levels shows that 79.2% of children and adolescents in Babu Township have urinary iodine levels exceeding 300 µg/L, indicating that most of the children are consuming more iodine than recommended by WHO. Although the human body has a high tolerance for iodine, individual iodine metabolism and the body's response to excessive iodine vary. The rising goiter rate in Babu Township children may be related to long-term excessive iodine intake, disrupting the original iodine balance in the population. Further research is needed to understand this issue.
Conclusion: Babu Township in Zhijin County represents only a part of the coal-burning fluorosis areas in Guizhou, where 37 counties are affected by fluorosis. Historically, these areas were mild or non-IDD regions. Whether other areas might experience similar conditions as Babu Township should be closely monitored.
References:
WHO/UNICEF/ICCIDD. Assessment of iodine deficiency disorders and monitoring their elimination: a guide for program managers. WHO, 2001.
Zhao Wenyuan, Zhu Huimin, Gao Youzhen, et al. Study on the combined effects of high iodine and high fluoride on experimental thyroid and fluorosis. Hebei Medical Journal, 1989, 10:69-72.
Xu Baoquan. Experimental study on the impact of chronic fluorosis on the thyroid gland. Journal of Clinical and Experimental Pathology, 1990, 6:4.
Yu Yanni, Dong Zhong, Liu Jialiu. Stereological parameters of the thyroid gland in fetuses from fluorosis areas in Guizhou. Chinese Journal of Endemiology, 1998, 13:148.
Li Xianji. Geological and epidemiological prediction of fluorosis endemic areas in Guizhou. Geological Geochemistry, 1982, 12:89-92.
Duan Rongxiang, Li Ping, An Dong, et al. Relationship between coal-burning and endemic goiter in Guizhou. Environmental Geochemistry and Health, Beijing: Seismological Press, 1987, 8-10.