| BackgroundThe trace element iodine is necessary for the human body.If the iodine of human body is insufficient or excessive,it may cause disease.In China,the determination of iodine deficiency disease area and water source high iodine area is based on the external environment iodine level,the iodine nutrition level of the population,the local goiter and the condition of cretinism,mainly based on the iodine content of the external environment.Generally,there is a significant correlation between water iodine content and iodine nutritional status of the population.GIS is a system that can store,analyze,display and output spatial or geographical data.Today GIS has been widely used in the medical field.However,there is no report on the distribution and use of iodine nutrition in key population in Shandong Province.Objective1.To understand and master the distribution of iodine content in drinking water of residents in Shandong Province,build a county-level water iodine content GIS data management platform in Shandong Province,and provide data support for redefining different types of water iodine regions.2.To understand and master the iodine nutrition status of children and pregnant women in Shandong Province.The GIS data management platform is built to provide a basis for taking targeted prevention measures and scientifically adjusting prevention strategies.3.To analyze the iodine nutritional status of the key population in different water iodine areas,and to provide basis for further implementation of the prevention and control strategy of adjusting measures to local conditions,classification guidance and scientific iodine supplement.MethodsThe survey of water iodine content was carried out in 137 counties in 17 cities in the province with the township as the unit.The survey on the iodine nutrition status of key populations divided the townships under the jurisdiction of each county in the province into five districts in the east,west,south,north,and middle,and one township was randomly selected from each district.The central primary school of each township was selected,and forty non-boarding students aged 8-10 were randomly selected from each primary school.In addition,each monitoring county selected 20 pregnant women in each of the 5 townships.Urine samples of the students and pregnant women were collected at random once during the day to determine the content of urinary iodine.Meanwhile,the thyroid size of the students were measured by B-ultrasound method.The data was cleaned up using Excel,the data was processed and analyzed by SPSS 24.0 software,and the distribution map of iodine nutrition status of water iodine and key populations was constructed using ArcGis 10.2 software.Spearman rank correlation analysis,Kruskal-Wallis H test,and χ2 test were used.The differences were statistically significant at P<0.05.Results1.Iodine content in drinking waterA total of 1,844 townships in 137 counties were surveyed,and the median water iodine in the province was 9.20μg/L.There were 74 counties with a median water iodine content of<10μg/L,accounting for 54.01%,in addition to Heze and Liaocheng,the other 15 cities were distributed;there were 41 counties between 10～<40μg/L,accounting for 29.93%,in addition to Zaozhuang,Yantai,Laiwu,Linyi,Liaocheng and Heze,the remaining 11 cities were distributed;there were 8 counties between 40～100μg/L,accounting for 5.84%,mainly distributed in Jinan,Qingdao,Jining,Liaocheng and Heze;there were 14 counties>100μg/L,accounting for 10.22%,mainly distributed in Heze,Liaocheng,Zibo and Jining.Among the 1,844 townships surveyed,there were 969 townships with a median water iodine<10μg/L,accounting for 52.55%;there were 489 townships between 10～<40μg/L,accounting for 26.52%;there were 139 townships between 40～100μg/L,accounting for 7.54%;there were 247 townships with>100μg/L,accounting for 13.39%.Among them,Jinan,Zibo,Dongying,Weifang,Jining,Tai’an,Dezhou,Liaocheng and Binzhou can see the coexistence of towns with different water iodine content.2.Urine iodine in childrenA total of 27,754 urine samples were collected from children in this survey.The urine iodine range was 0.00～5510.00μg/L,and the median urine iodine in children was 201.90μg/L.There were 73 counties in the province with median urinary iodine of 100～<200μg/L,in addition to Heze,the remaining 16 cities were distributed;there were 46 counties in the range of 200～<300μg/L,all cities were distributed;there were 17 counties≥300μg/L,mainly distributed in Jinan,Zibo,Jining,Linyi,Dezhou,Liaocheng and Heze;the median urinary iodine of children in one county was<100μg/L.distributed in Tai’an.The counties with the median urinary iodine≥300μg/L for children were mainly distributed in the areas north and south of the Yellow River and west of the Beijing-Hangzhou grand canal.The correlation coefficient between the median water iodine and the median urinary iodine in children at the county level was r=0.383(P<0.001).In areas with a median water iodine of<10μg/L and 10～<40μg/L,children’s urine iodine levels were in the appropriate range of iodine;In areas with a median water iodine of 40～100μg/L,the levels of urinary iodine in children were greater than the appropriate amount;In areas with a median water iodine of>100μg/L,urinary iodine levels in children were in excess.The median urinary iodine of children in each water iodine group increased with the increase of water iodine content.There were statistically significant differences in urinary iodine levels among children in different water iodine regions(H=2909.119.P<0.001).There were statistically significant differences between the two groups of water iodine(P<0.001).3.B-ultrasound in childrenA total of 27,754 people were examined for thyroid ultrasound in this survey,of which 675 had goiter,and the rate of onychomycosis was 2.43%.There were 2 counties of children nail swelling rate≥15%,distributed in Dezhou and Binzhou;there were 2 counties,the goiter rates were between 10%～<15%,which was distributed in Jining;there were 17 counties,the goiter rates were between 5%～<10%,mainly distributed in Qingdao,Zibo;Dongying,Yantai,Jining,Tai’an,Dezhou,Liaocheng and Heze;the goiter rates of children in other 116 counties were less than 5%.There was no significant correlation between water iodine median and goiter rate(P=0.315).The highest goiter rate was found in regions with median water iodine of 10～<40μg/L,which was 3.31%,the lowest goiter rate was found in regions with median water iodine of 40～100μg/L,which was 1.75%.There were statistically significant differences in the goiter rate among children in different iodine regions(χ2=48.185,P<0.001).There were statistically significant differences between regions with water iodine median<10μg/L and 10～<40μg/L or>100μg/L(χ2=43.040,P<0.001;χ2=9.769,P=0.002);There was a statistically significant difference in the area between 10～<40μg/L and 40～100μg/L(χ2=10.968.P=0.001).There were no significant differences between the other groups(P>0.0083).4.Pregnant women urine iodineA total of 12,904 urine samples were collected from pregnant women.The range of urine iodine was 0.00～7735.00μg/L,and the median of urine iodine was 152.70 μg/L.There were 70 counties with a median urine iodine of<150μg/L in pregnant women,accounting for 51.09%,and they were distributed in all cities;there were 50 counties between 150～<250μg/L,accounting for 36.50%,except Laiwu all over the city were distributed;there were 14 counties between 250～<500μg/L,accounting for 10.22%,mainly distributed in Zibo,Yantai,Weifang,Jining,Laiwu,Dezhou,Heze and Liaocheng;there were 3 counties≥500μg/L,distributed in Jining,Liaocheng and Heze.The correlation coefficient between the median of water iodine at the county level and the median of urine iodine in pregnant women was r=0.186(P=0.029).In the areas where the median of water iodine<10μg/L and 10～<40μg/L,median urinary iodine in pregnant women was at the lower limit or slightly lower than the appropriate level;in regions with a median water iodine of 40～100μg/L.median urinary iodine in pregnant women was at the appropriate level;in regions with a median water iodine of>100μg/L,median urinary iodine in pregnant women was slightly greater than the appropriate level.There were statistically significant differences in the urinary iodine levels of pregnant women in different water iodine regions(H=316.885,P<0.001).There was no significant difference between regions with median water iodine<10μg/L and 10～<40μg/L(P=1.00),but there were significant differences between other groups(P<0.05).Conclusions1.Most of the areas in Shandong Province are iodine deficient areas,and there are a certain proportion of "suitable iodine" areas and water high iodine areas,and some areas can see the phenomenon of staggered distribution.The areas with high iodine content are mainly distributed both banks of the Yellow River to the west of the Beijing Hangzhou Grand Canal,and the areas with iodine deficiency are mainly distribut in Shandong Peninsula,the central mountainous area and the southern hills.2.According to the WHO/UNICFF/IGN recommend evaluation standard of iodine nutritional status of the population,the iodine nutrition of children in the province is at the lower limit of the optimum level,but it do not reach the level of iodine excess.Most of the counties are at the appropriate level of iodine nutrition,and children in some counties are at risk of iodine overdose.In the area of high water iodine,the iodine nutrition of children is obviously excessive.On the whole,the goiter rate of children in Shandong Province is at a low level,but in some counties,the goiter rate of children is higher.In the area with water iodine median of 40～100μg/L,the goiter rate of children is the lowest.The iodine nutrition of pregnant women in the province is at the lower limit of the appropriate level,and pregnant women still have the risk of iodine deficiency.Especially in the areas with water iodine median<40μg/L,the iodine nutrition level of pregnant women is at the lower limit of iodine deficiency or appropriate level,and the risk of iodine deficiency of pregnant women is higher.3.According to the status of urine iodine in children,goiter rate in children and urine iodine in pregnant women,it is suitable to set the standard of water iodine in"suitable iodine" area as 40～100μg/L. |
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