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Objective:To explore the medical reference values, distribution characteristics and influencing factors of serum iodine in adults with different thyroid health conditions, and to evaluate the importance of serum iodine in evaluating individual iodine nutrition.Methods:From February 2017 to November 2018, multi-stage stratified cluster sampling was used to select one community and one agricultural (fishing) village in the coastal Yingkou City and the inland areas of Shenyang City of Liaoning Province as survey sites. Cluster sampling of adults over 18 years old who had lived for five years were conducted with questionnaire survey, clinical physical examination and thyroid ultrasound examination. Fasting venous blood samples and one random urine sample were collected from all subjects for serum iodine, thyroid hormone, antibody and urine iodine detection. The 95% medical reference value of serum iodine was established by using the percentage quantile method, and the reference value, distribution characteristics and influencing factors of serum iodine in adults with different thyroid health status were analyzed. The diagnostic value of iodine nutritional indicators in thyroid diseases was evaluated by the receiver operating characteristic (ROC) curve.Results:A total of 2 931 adults were surveyed, with serum iodine levels of 62.1 (53.6, 72.2) μg/L, ranging from 5.6 to 642.3 μg/L; urine iodine was 167.6 (111.2, 244.2) μg/L, and the overall iodine level was at an appropriate level. A total of 1 089 patients with thyroid diseases were examined, with a detection rate of 37.2% (1 089/2 931); among them, there were 597 cases of thyroid nodules, 56 cases of endemic goiter, 42 cases of hypothyroidism, 161 cases of subclinical hypothyroidism, 27 cases of hyperthyroidism, 18 cases of subclinical hyperthyroidism, and 474 cases of autoimmune thyroid disease (AITD). There was a statistically significant difference in the detection of thyroid diseases among adults with different levels of serum iodine (χ 2 = 13.80, P < 0.05). The reference values of serum iodine in normal adults, hypothyroidism (without thyroid hormone intervention), hyperthyroidism (without anti thyroid hormone drug treatment), AITD, endemic goiter, and thyroid nodules were 37.2 - 103.0, 12.5 - 52.8, 49.9 - 163.1, 34.3 - 129.3, 27.3 - 92.8, and 37.9 - 119.5 μg/L, respectively. The ROC curve analysis results showed that the serum iodine area under curve(AUC) of patients with hyperthyroidism, subclinical hyperthyroidism, endemic goiter, thyroid nodules, and AITD were 0.94, 0.61, 0.55, 0.53, and 0.52, respectively. The results of univariate analysis showed that there were statistically significant differences in adult serum iodine levels among different positions, regions, age, education level, occupation, iodine intake, blood pressure, and body mass index ( P < 0.05). Conclusions:There are significant differences in serum iodine levels among adults with different thyroid health conditions, and evaluation standards and systems should be developed separately. Serum iodine is an important indicator for evaluating individual iodine nutrition.
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Objective:To learn about the levels of serum iodine and thyroid function indicators in adults with normal thyroid function in Liaoning Province, to establish the medical reference value range of serum iodine, and to explore the relationship between serum iodine and thyroid function indicators.Methods:From February 2017 to December 2018, one subdistrict and one rural township were selected as the survey sites in the coastal area (Gaizhou City of Yingkou) and inland area (Kangping County of Shenyang) of Liaoning Province, respectively. Permanent residents aged 18 and older who have lived there for 5 years or more were selected as the survey subjects. Blood samples were collected to test the levels of serum iodine and thyroid function indicators [thyroid stimulating hormone (TSH), free triiodothyronine (FT 3), free thyroxine (FT 4), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb)]. The percentile method was used to establish the 95% medical reference value range of serum iodine in adults with normal thyroid function, and Pearson correlation analysis was used to analyze the correlation between serum iodine and thyroid function indicators. Results:A total of 1 621 adults with normal thyroid function were examined, the median serum iodine was 62.0 μg/L, and the 95% medical reference value range was preliminarily determined as 37.0-103.0 μg/L. Among them, the medians serum iodine of males and females (826 and 795 cases) were 62.3 and 61.0 μg/L, respectively, and there was no significant difference between genders ( Z=- 1.26, P = 0.210). The medians serum iodine of adults in coastal and inland areas (827 and 794 cases) were 61.7 and 61.9 μg/L, respectively, and there was no significant difference between areas ( Z = - 0.16, P = 0.870). The medians serum iodine of adults aged 18 - 29, 30 - 39, 40 - 49, 50 - 59 and 60 - 80 (385, 392, 378, 253 and 213 cases) were 61.0, 61.0, 63.0, 65.0 and 62.0 μg/L, respectively, and the difference between ages was statistically significant ( H = 14.52, P = 0.006). Pearson correlation analysis showed that serum iodine was weakly correlated with the level of FT 4 ( r = 0.17, P < 0.001), but not with the levels of TSH, TPOAb and TgAb ( P > 0.05). Conclusions:This study has established the medical reference value range of serum iodine in adults with normal thyroid function in Liaoning Province. Serum iodine is not correlated with the levels of TSH, TPOAb and TgAb.
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Objective:To understand the urinary iodine external quality control assessment results of county-level iodine deficiency disorders laboratories in Liaoning Province.Methods:The numbers of county-level iodine deficiency disorders laboratories which participated in the national urinary iodine external quality control assessment in Liaoning Province from 2016 to 2019 were 19, 33, 39 and 56, respectively. The urinary iodine external quality control assessment results were statistically analyzed with the Z score method (qualified: │Z│≤2; basically qualified: 2 <│Z│ < 3; unqualified: │Z│≥3). The percentage of laboratories participating in the assessment and the qualified rate were calculated.Results:From 2016 to 2019, the percentage of county-level iodine deficiency disorders laboratories in Liaoning Province that participated in the national urinary iodine external quality control assessment increased year by year, which were 19.79% (19/96), 34.38% (33/96), 40.63% (39/96) and 58.33% (56/96), respectively. The qualified rates were 89.47% (17/19), 84.85% (28/33), 100.00% (39/39) and 100.00% (56/56), respectively.Conclusion:From 2016 to 2019, the percentage and detection capacity of county-level iodine deficiency disorders laboratories in Liaoning Province that participated in the national urinary iodine external quality control assessment have been improved.
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Objective To analyze the iodine nutritional status of children and pregnant women in Liaoning Province,and the iodine content of edible salt suitable for iodine nutrition level,to provide a basis for adjusting the suitable salt iodine content standard of key population.Methods In 2015-2018,a cross-sectional survey method was used to conduct iodine nutritional status surveys in counties (districts) within the jurisdiction of Liaoning Province.One township (community) was selected in each county (district)according to the east,west,south,north,and middle directions.Forty children aged 8-10 (age and gender distribution balanced) and 20 pregnant women were selected in each township (community),urine and household salt samples were collected from children and pregnant women,to test urine and salt iodine levels;and the water samples from all township (community) water supply plants in the province were collected for water iodine detection in 2017;and all respondents were calculated the dietary iodine intake.The multi-order linear curve was used to fit the salt iodine content suitable for children and pregnant women.Results A total of 1 549 townships (communities) were surveyed,including 1 125 centralized water supply townships (communities) with water iodine ＜ 40 μg/L;50 820 children aged 8-10 and 26 707 pregnant women were selected from the centralized water supply towns.The average iodine content of edible salt was 24.0 and 23.9 mg/kg,respectively.The median urinary iodine level of children was 168.5 μg/L,at the appropriate level of iodine;the median urinary iodine level of pregnant women was 137.8 μg/L,at the deficiency level of iodine.The average dietary intake of iodine in children was 228.4 μg/d,which was 3.51 times of the standard iodine requirement (EAR,65 μg/d) and 2.54 times of the recommended intake (RNI,90 μ g/d).The average dietary intake of iodine in pregnant women was 273.4 μg/d,which was 1.71 times of the EAR (160 μg/d) and 1.19 times of the RNI (230 μg/d),and 21.4％ (5 728/26 707) of pregnant women had lower iodine intake than RNI,the iodine intake was insufficient.After multi-level linear curve fitting combined with monitoring data,the iodine content range of edible salt in children's urine was suitable and the iodine intake in RNI-tolerable intake (UL,300 μg/d) was 13-25 mg/kg (20 mg/kg + 20％);the iodine content range of edible salt in pregnant women's urinary iodine was suitable and the iodine intake in RNI-UL (600 μg/d) is 25-37 mg/kg (31 mg/kg + 20％).Conclusions Under the current salt iodine content standard (25 mg/kg) in Liaoning Province,children's iodine nutrition is generally at the level of iodine appropriate;pregnant women's iodine nutrition is generally at the level of iodine deficiency.It is recommended that all regions should revise the iodine content standard for edible salt in due course in combination with the iodine nutritional status of key populations within the jurisdiction.
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Objective Software Origin was used to evaluate urine iodine external quality control results in Liaoning Province in 2017,and to promote the application of software Origin in laboratory proficiency testing and to improve the urine iodine detection capability of laboratories in Liaoning Province.Methods In 2017,1 provincial-,14 municipal-and 33 county-level disease prevention and control institution laboratories in Liaoning Province were numbered,1-15:provincial and municipal levels,16-48:county-level.Software Origin 9.5 was used to produce the Z-ratio histogram,the deviation bar graph of repeated measurement results and the Youden plot of urine iodine external quality control results.When ｜Z｜ ≤2,it was satisfactory;when 2 ＜ ｜Z｜ ＜ 3,it indicated problems;when ｜Z｜ ≥3,it was not satisfactory.Based on ｜ Z｜ scores of laboratories,systematic errors and random errors were analyzed.Results Most laboratories had scores of ｜Z｜ ≤2,the results were satisfactory.Laboratory 36 had scores of ｜Z｜ ＞ 3,the result was not satisfactory,there were both systematic errors and random errors.The deviation bar graph of repeated measurement results showed that the precision of the high concentration test results in laboratory 21 was poor.Conclusions The software Origin is suitable to evaluate laboratory proficiency testing.The capacity of urine iodine detection in the county-level laboratories in Liaoning Province needs to be improved.Systematic errors and random errors still exist in individual laboratories.It is necessary to find the causes of errors,and strengthen laboratory internal quality control and improve the quality of the laboratory.
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Objective To study the status of prevention and control of iodine deficiency disorders (IDD),master the iodine nutritional status of children and pregnant women in Liaoning Province.Methods One hundred counties (districts) of Liaoning Province,34 counties (districts) were randomly selected to carry out a cross-sectional survey on iodine nutritional status of the population according to "National Surveillance Program on IDD" in 2016.Five townships (communities) were randomly selected according to their sub-area positions of east,west,south,north and center,1 primary school was randomly selected in each township (communities),40 non boarding students aged 8-10 (half males half females) were selected from each school.The radial size of the thyroid was measured by Ultra-portable Doppler Diagnostic Ultrasound System and the volume was calculated.Twenty pregnant women were randomly selected in each township (communities).Their salt and random urine samples were collected;salt iodine level and urinary iodine level were tested.Results The mean of salt iodine content of 6 874 children's family salt samples was (24.0 ± 4.7) mg/kg,the iodized salt coverage rate was 98.4％ (6 761/6 874) and the consumption rate of qualified iodized salt was 95.5％ (6 567/6 874).The median urinary iodine (MUI) of 6 874 children's urine samples was 168.0 μg/L,and children's goiter rate was 1.6％ (111/6 874).The mean of salt iodine content of 3 404 pregnant women's family salt samples was (24.1 ± 4.3) mg/kg,the iodized salt coverage rate was 99.0％ (3 369/3 404) and the consumption rate of qualified iodized salt was 84.6％ (2 880/3 404).The MUI 3 404 of pregnant women's urine samples was 135.8 μg/L (＜ 150 μg/L).Conclusions In 2016,8-10 years old children's urinary iodine is at adequate level.But the pregnant women are in iodine deficiency.
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Objective To evaluate the detection capability in determining water fluoride at center for disease control and prevention (CDC) of Liaoning Province, and to promote the improvement of detection quality. Methods The detection results of the external quality assessment of fluoride in water from 66 CDC labs in Liaoning Province in 2016 were analyzed by using standard Z score. The potential outliers were determined by Youden plot. The determine standard of the Z score:│Z│≤2 was satisfacted;2<│Z│<3 was qualified,but suggesting there was a problem, need to find the cause of the error; │Z│≥3 was not satisfied. Results According to the results of standard Z score,there were 66 labs satisfacted, the satisfacted rate was 100.0% (66/66). According to the Youden plot, there were 4 possible outliers (6.1%, 4/66) which need to be rechecked. Conclusions The capability in determining water fluoride at CDC of Liaoning Province meet the standards, but individual laboratories need to improve the quality of testing. The internal quality control of the laboratory is very important. All CDCs should improve the detection capability continuously.
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Objective To master the prevalence of drinking-water-borne endemic fluorosis of children in the disease affected areas of Liaoning Province and to understand the effect of water improvement measures in prevention and control of fluorosis.Methods The data of 18 water improvement projects in drinking-water-borne endemic fluorosis areas of Liaoning Province from 2011 to 2016 were collected by retrospective method,and the data of dental fluorosis in children aged 8 to 12 years old were analyzed.The prevalence and detection rate of dental flaorosis in children aged 8 to 12 years old were analyzed.To compare the incidence of dental fluorosis among children from villages with qualified water fluoride and those from villages with unqualified water fluoride.Results From 2011 to 2016,in the annual survey of 18 water engineering projects in 18 monitored villages,normal operating rate was between 94.44％ (17/18)-100.00％ (18/18),water fluoride qualified rate was between 88.89％ (16/18)-100.00％ (18/18).In the monitored village,4 941 children aged 8 to 12 were examined,and the detection rate of dental fluorosis was 9.8％ (484/4 941).The dental fluorosis index was 0.19.The detection rate (14.0％,10.7％,10.7％,8.7％,6.6％,8.1％) of dental fluorosis was decreasing year by year (x2trend =24.3,P ＜ 0.05).The total detection rate of children's dental fluorosis in monitored villages (8.1％,356/4 422) with normal operation of water improvement projects and qualified water fluoride was lower than that in monitored villages with excessive water fluoride (24.7％,128/519,x2 =145.1,P ＜ 0.05).Conclusion After water improvement measures are implemented in drinking water fluorosis areas of Liaoning Province,the dental fluorosis of children in the affected areas is effectively controlled,but the problem of excessive fluoride in water improvement projects still exists,and the management of water improvement projects should be strengthened in the future.
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Objective To evaluate the detection capability for salt iodine test by using graphic method,and to provide reliable detection data for prevention of iodine deficiency disorders.Methods The examination results of external quality assessment for disease control mechanism in Liaoning Province in 2013 were analyzed by using standard Z score and Youden plot.The level of reproduction and type of error were analyzed by Z score sequence diagram in order to find the outliers and results need to be reviewed by the Youden plot.Salt iodine was detected by the general test method in salt industry for determination of iodine (GB/T 13025.7-2012).Results According to single sample evaluation of the Z score,111 laboratories were qualified,the qualified rate was 97.4％ (111/114).Three labs were not qualified,unqualified rate was 2.6％ (3/114).According to double sample evaluation of the Z score,112 laboratories were qualified,the qualified rate was 98.2％ (112/114).Two laboratories were not qualified,unqualified rate was 1.8％ (2/114).According to the Youden plot,5 laboratories were possible outliers with results need to be reviewed.Conclusion Statistical graphic method has displayed the examination results directly,which is helpful in searching targeted improvements,and improving the detection capability.
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Objective To understand the condition of iodine deficiency disorders,and the iodine nutritional status of population before adjustment of iodine level in edible salt in Liaoning Province.Methods Thirty countries (cites,districts) which were divided into coastal,inland,city,rural areas according to location and population characteristics were sampled by population probability sampling method in the whole province; one township (town,street office) was sampled from each country (city,district); one village (neighborhood) and one school were chosen from each township(town,street office).Forty children aged 8-10 were selected from each school to measure their thyroid volumes and household salt samples were collected to detect their iodine content; fourteen of those 40 children were selected to detect their urinary iodine content.In each village (neighborhood),five drinking water samples were collected in the east,the west,the south,the north and the center positions.Two tap water samples were collected to detect their iodine content if the water supply was centralized.Around each school; three townships were selected,in each township,random urine samples were collected from 5 pregnant women and 5 lactating women to detect their iodine content.Thyroid volume was examined by ultrasound method; the salt iodine was tested by the method of direct titration; iodine content of urine and drinking water was tested by arsenic cerium catalytic spectrophotometry.Results Totally one thousand two hundred and nineteen children aged 8-10 were examined; twenty-nine children were diagnosed goiter,and the goiter rate was 2.4％(national standards:＜ 5％).One thousand two hundred and nineteen edible salt samples were tested,and the median salt iodine level was 30.1 mg/kg.The iodized salt coverage rate was 99.3％(1 211/1 219),and the consumption rate of qualified iodized salt was 97.9％(1 194/1 219).Four hundred and eighty urine samples were tested,and the median urinary iodine level was 189.0 μg/L(suitable content of salt iodine was 100-199 μg/L) ; urinary iodine ＜ 20 μg/L accounted for 0.6％(3/480).Ninety-nine drinking water samples were selected,and the average iodine content of the drinking water was (5.9 ± 5.7)μg/L.Four hundred and fifty-one urine samples of pregnant women and four hundred and fifty urine samples of lactating women were selected,and the median urinary iodine level of pregnant women and lactating women was 163.2,151.0 μg/L(suitable contents of urinary iodine in pregnant women and lactating women were 150-249 μg/L,＞ 100 μg/L).The median urinary iodine of pregnant women was 135.4 μg/L in coastal city,138.0 μg/L in coastal rural,168.0 μg/L in inland city,171.1 μg/L in inland rural.The difference of urinary iodine between coastal region and inland region was significant(H =14.287 6,P ＜ 0.05).Conclusions The iodine nutrition conditions of pregnant women,lactating women and children are adequate in Liaoning Province,but the iodine nutritional status is insufficient in pregnant women from the coastal areas.
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Objective To study the effect of different iodine nutrition on thyroid function in adult and pregnant women.Methods A random sampling method was used to select healthy adult and pregnant woman from the communities of coastal city,coastal rural and inland rural areas in Liaoning Province.Drinking water,urine and salt samples were collected to measured urinary iodine (U I),salt iodine (SI) and water iodine content.Fasting venous blood was collected to measured thyroid stimulate hormone (TSH),freethyroxine (FT4),free triiodothyronine (FT3),thyroglobulin antibody (TgAb) and thyroid peroxidase antibody (TPOAb) with the method of immunoassay chemical luminescence.Results A total of 150 salt samples were collected,means of SI was (30.1 ± 6.0)mg/kg.A total of 72 pregnant woman and 271 adults were investigated in iodized salt supplied regions.median UI of pregnant woman and adults were 176.3,203.2 μg/L.Iodine nutrition of pregnant women and coastal region adults was in an adequate level.Means of SI of inland adults(244.4 μg/L) was higher than appropriate level but not reached the excessive level.FT4 of the adults (11.7 pmol/L) and pregnant women (10.7 pmol/L) in inland regions were slightly higher than that of coastal city,rural adults(11.2,8.6 pmol/L) and pregnant women (10.9,9.6 pmol/L).TSH,FT3 and FT4 were not statistically different between regions (all P ＜ 0.05).But UI,FT4 and FT3 levels of pregnant women(176.3 μg/L,9.5 pmol/L,4.3 pmol/L) were significantly lower than that of the adults(203.2 pμg/L,11.3 pmol/L,4.7 pmol/L,all P ＜ 0.05).Hypothyroxinemia(4.4％,10/173) was higher than that of the inland adults (2.0％,2/98,P ＜ 0.05).And all hypothyroxinemia were found in women of childbearing age.Hypothyroxinemia prevalence of pregnant women(16.7％,12/72) was higher than that of adults(4.4％,12/271,P ＜ 0.05),The prevalence of hypothyroidism,hyperthyroidism and subclinical hyperthyroidism between the 3 regions adults and pregnant women were not statistically different (all P ＞ 0.05).Conclusions Under appropriate supply conditions of iodized salt,iodine nutrition and thyroid function are closely related.Pregnant women and women of childbearing age are at risk of iodine deficiency.The thyroid function of these people should be strengthen detect.