Effect of thiocyanate levels in milk on thyroid function in iodine deficient subjects

To utilize the antibacterial effect of the lactoperoxidase system to prevent bacterial spoilage of raw milk it is necessary to increase the thiocyanate concentration of the milk. Thiocyanate has, however, a potent antithyroid effect which is enhanced by iodine deficiency. In this study the thyroid function has been studied, before and after 4 weeks daily administration of 250 ml of such treated milk, in 55 goitrous subjects living in an endemic goiter region of western Sudan. The iodine content was 0.1 mg/l and the thiocyanate content was either 3.6 mg/l (n 19) or 19 mg/l (n 36) in the milk. At the start of the experiment all subjects were iodine deficient with a urinary excretion of 40-50 micrograms/g creatinine. After 4 weeks daily intake of 4.75 mg of thiocyanate by way of milk the serum thiocyanate level increased by approximately 1.7 mg/l. Both at the beginning and at the end of the experimental period the serum levels of thyroxine, triiodothyronine and TSH were in the normal range for all subjects. After 4 weeks the TSH levels had decreased significantly, (from 2.6 +/- 0.2 to 2.1 +/- 0.2 mU/l, p less than 0.001) probably as an effect of the supplementary intake of iodine. The thyroid hormone levels remained unchanged during the experimental period. In conclusion, the intake of milk with an iodine concentration of 0.1 mg/l and a thiocyanate concentration of 19 mg/l does not have a negative effect on the thyroid function in iodine deficient subjects.     

Widespread endemic goiter and iodine deficiency in the province of Avellino

1352 schoolchildren between 6-14 years old (699 males and 653 females) and 943 adults (176 males and 767 females) from eight villages of the province of Avellino were studied. All subjects were examined for thyroid size by at least two expert examiners. In most of them urine samples were collected for iodine determinations. 387 schoolchildren and 161 adults from Flumeri and Villanova were evaluated by thyroid echography. The prevalence of goiter was from 23.5 to 52.2% and the median urinary iodine excretion was from 42.3 to 66.2 micrograms/l in schoolchildren. In adults the prevalence of goiter was from 41.2 to 86.7% and the median urinary iodine excretion was from 37.1 to 53.7 micrograms/l. Our data showed a degree of iodine deficiency from low to moderate. The echography permitted to point out a greater prevalence of nodules than the thyroid palpation.     

Quantification of urinary iodine: a need for revised thresholds

OBJECTIVE: To compare different possibilities of reporting the iodine supply in the same urine samples. Indeed, in field studies, urinary iodine concentration (I/L: micro g I/L, micro mol I/L, I/creatinine: micro g I/g creatanine, micro mol I/mol creatinine) is more readily available than excretion (I/24h micro g I/24 h, micro mol I/24h). However, confusion exists regarding the comparability of iodine supply based upon I/L, I/creatinine and I/24h, which for decades have been regarded as biochemically equivalent. DESIGN: We compared I/24h, I/L and I/creatinine in accurate 24 h collections of urine and I/L and I/creatinine in 47 spot urine samples. PATIENTS: A total of 13 subjects (Bern n=7, Brussels n=6) collected a total of 110 precise 24 h urine collections (Bern n=63, Brussels n=47). The subjects from Brussels also took a spot sample at the beginning of each 24 h collection. RESULTS: Iodine supply in both places was mildly deficient according to the criteria of WHO; all but one collection indicated an intake of >0.39 micro mol I/24h (>50 micro g I/24h). The same data presented as I/creatinine (or I/L) indicated an iodine intake of <0.39 (<50 micro g I/24h) in 5% (24%) of the samples in Bern and 23% (57%) in Brussels. Similar findings were observed for 47 spot samples. Whatever the cut-off selected, I/creatinine and I/L were systematically lower than I/24h (P<0.0002). Creatinine showed smaller CV than volume but did not perform better in defining iodine intake. CONCLUSION: Considering I/24h as a reference, both I/creatinine and I/L clearly underestimate the iodine intake in subjects with adequate proteoenergetic intake. The significant deviations observed illustrate the urgent need for establishing separate ranges for I/24h, I/creatinine and I/L. In population studies, these deviations might even be larger.     

Day-to-day and within-day variation in urinary iodine excretion.

OBJECTIVE: To examine the day-to-day and within-day variation in urinary iodine excretion and the day-to-day variation in iodine intake. DESIGN: Collection of consecutive 24-h urine samples and casual urine samples over 24h. SETTING: The study population consisted of highly motivated subjects from our Institute. SUBJECTS: Study 1: Ten healthy subjects (seven females and three males) aged 30-46 y. Study 2: Twenty-two healthy subjects (9 males and 13 females) aged 30-55 y. METHODS: Study 1: 24-h urine samples were collected for four consecutive days. Study 2: Each urine voided over 24 h was collected into separate containers. In both studies dietary records were kept. MAIN OUTCOME MEASURES: Twenty-four-hour urinary iodine excretion, 24-h urinary iodine excretion estimated as I/Cr*24 h Cr and as a concentration in casual urine samples. RESULTS: Study 1: Both iodine excreted in 24-h urine and iodine intake varied from day-to-day. Iodine excretion correlated with iodine intake (=-0.46, P=0.01). Iodine intake (mean 89 +/- 6.5 microg/d) was not significantly different from iodine excretion (mean 95 +/- 5.3 microg/d). Study 2: Twenty-four hour iodine excretion estimated as I/Cr*24 h Cr from the morning urine sample was significantly lower than actual 24-h iodine excretion, whereas 24-h iodine excretion estimated as I/Cr*24 h Cr from the first sample after the morning sample and the last sample before the subjects went to bed was not significantly different from actual 24-h iodine excretion. Twenty-four-hour urine excretion estimated as a concentration was lower than actual 24-h iodine excretion in casual urine taken at any time of the day. CONCLUSIONS: For determination of iodine status in an individual, more than one 24-h urine sample must be used. The use of the I/Cr ratio in casual urine samples is a usable measure of iodine status if corrected for the age- and sex-adjusted 24-h creatinine excretion. Further, the study suggests that fasting morning urine samples would underestimate iodine status in this population.     

Reliability of studies of iodine intake and recommendations for number of samples in groups and in individuals

The iodine intake level in a population is determined in cross-sectional studies. Urinary iodine varies considerably and the reliability of studies of iodine nutrition and the number of samples needed is unsettled. We performed a longitudinal study of sixteen healthy men living in an area of mild to moderate iodine deficiency. Iodine and creatinine concentrations were measured in spot urine samples collected monthly for 13 months. From these data we calculated the number of urine samples needed to determine the iodine excretion level for crude urinary iodine and for 24 h iodine excretion estimated from age- and gender-specific creatinine excretions. We found that mean urinary iodine excretion varied from 30 to 87 microg/l (31 to 91 microg/24 h). Sample iodine varied from 10 to 260 microg/l (20 to 161 microg/24 h). Crude urinary iodine varied more than estimated 24 h iodine excretion (population standard deviation 32 v. 26; individual standard deviation 29 v. 21; Bartlett's test, P < 0.01 for both). The number of spot urine samples needed to estimate the iodine level in a population with 95 % confidence within a precision range of +/- 10 % was about 125 (100 when using estimated 24 h iodine excretions), and within a precision range of +/- 5 % was about 500 (400). A precision range of +/- 20 % in an individual required twelve urine samples or more (seven when using estimated 24 h iodine excretions). In conclusion, estimating population iodine excretion requires 100-500 spot urine samples for each group or subgroup. Less than ten urine samples in an individual may be misleading.     

Iodine content of human milk and dietary iodine intake of Korean lactating mothers

Korea's food culture includes the consumption of seaweed, which is abundant and has a high iodine content. Because it is customary to serve seaweed soup to new mothers, the consumption of seaweed increases dramatically when a woman is lactating. The present study was undertaken for the purpose of determining the iodine content in human milk of Korean lactating mothers according to dietary iodine intake. The iodine content of human milk and dietary iodine intake from 50 lactating mothers were analyzed at 2 to 5 days and at 4 weeks postpartum. The dietary iodine intake was assessed by the 24-hour recall method. The iodine content in human milk was analyzed by neutron activation analysis (NAA). The average daily iodine intake of lactating mothers was 2744 micrograms at 2 to 5 days postpartum, decreasing significantly to 1295 micrograms at 4 weeks postpartum. The major sources of iodine were seaweed (87%) and cows' milk (7%). The average iodine content in colostrum and mature milk was 2170 micrograms/l and 892 micrograms/l, respectively. There was a significant reduction in the levels of iodine in human milk depending on the lactation period. A significant correlation between maternal iodine intake and iodine content of human milk was observed (P < 0.0001). The frequency of seaweed soup intake in lactating mothers seems to be a modifying factor in the iodine intake level and the iodine content in human milk. The level of dietary iodine intake and the iodine content of breast milk of Korean lactating mothers is found to be much higher than in other countries.     

天津市售食品碘含量及部分大学学生碘营养状况的研究

目的了解当前市售食品碘含量,部分大学生膳食碘营养状况,碘盐对膳食摄入碘的补充作用,以及尿碘测定结果对膳食碘的反映程度。方法分层随机采集日常市售食物278份,采用砷铈接触法测定食品碘含量,膳食记录法调查学生的7日膳食情况,砷铈催化分光光度法测定尿碘。结果47种、278份食物样品的检测表明,动物性食品的含碘量（7．8ug／100g～30．8ug／100g）高于植物性食品的含碘量（1．8ug／100g～16．1ug／100g）。膳食调查显示该类学生中以素食为主的占70．19％,以食物碘含量的实测值和膳食调查结果计算出由食物中摄入碘的量为（111．67±53．18）ug/d,而从碘盐中补充碘量（230．27±45．55）ug／d,那么从膳食中共可以摄入碘（341．95±89．58）ug/d。经尿肌酐校正后每克肌酐尿中碘含量中位数为271．28ug／gCr。经尿肌酐校正后的尿含碘量与膳食摄碘量呈正相关关系（0=0．463,P〈0．01）。结论这部分学生多数来自低收入家庭且膳食以素食食物为主,每日从膳食中摄入的碘量低于碘的推荐供给量（RDA）150ug,但是从加碘食盐中可以获得碘230．27ug,从而弥补膳食摄碘量的不足。     

Restricted intraindividual urinary iodine concentration variability in nonfasting subjects

OBJECTIVE: Individual urinary iodine concentration (UIC) reflects iodine intake over a short time prior to sampling. Since eating habits are relatively constant in single subjects, UIC should be relatively constant in a given individual. The aim of our study was to verify this hypothesis by assessing UIC in repeated single urine samples from a group of healthy subjects. DESIGN AND SETTING: A prospective sequential investigation was performed in 131 volunteer health workers or students recruited in our University hospital. INTERVENTIONS: Single urine samples were taken in a nonfasting state, between 0900 and 1100 hours. Group 1 was composed by 131 subjects who collected one urine sample. Group 2 was composed by 11 subjects of the group 1, who collected multiple repeated urine samples (as a whole 158 urine samples, mean 14 samples each). UIC mean+/-s.d., median and coefficient of variation (CV%) was measured in both groups. RESULTS: Interindividual UIC variation was wide, UIC ranging from 21 to 382 microg/l, mean 136+/-84 microg/l, median 124 microg/l, CV 62%. Also in the 11 subjects repeatedly sampling there were considerable differences among individual UIC average levels (ranging from 37+/-15 to 221+/-91 microg/l). However, in this second group, the intraindividual variation was considerably restricted (CV% 36). CONCLUSIONS: The present study shows that in a nonfasting state in mid-morning UIC is more stable from day to day in a single subject, depending on his eating habits, than in various subjects. Thus, a single urine sample even in nonfasting state may give some rough information about the individual's iodine status.     

Geographical distribution of drinking-water with high iodine level and association between high iodine level in drinking-water and goitre: a Chinese national investigation

Excessive iodine intake can cause thyroid function disorders as can be caused by iodine deficiency. There are many people residing in areas with high iodine levels in drinking-water in China. The main aim of the present study was to map the geographical distribution of drinking-water with high iodine level in China and to determine the relationship between high iodine level in drinking-water and goitre prevalence. Iodine in drinking-water was measured in 1978 towns of eleven provinces in China, with a total of 28,857 water samples. We randomly selected children of 8-10 years old, examined the presence of goitre and measured their urinary iodine in 299 towns of nine provinces. Of the 1978 towns studied, 488 had iodine levels between 150 and 300 μg/l in drinking-water, and in 246 towns, the iodine level was >300 μg/l. These towns are mainly distributed along the original Yellow River flood areas, the second largest river in China. Of the 56 751 children examined, goitre prevalence was 6.3 % in the areas with drinking-water iodine levels of 150-300 μg/l and 11.0 % in the areas with drinking-water iodine >300 μg/l. Goitre prevalence increased with water and urinary iodine levels. For children with urinary iodine >1500 μg/l, goitre prevalence was 3.69 times higher than that for those with urinary iodine levels of 100-199 μg/l. The present study suggests that drinking-water with high iodine levels is distributed in eleven provinces of China. Goitre becomes more prevalent with the increase in iodine level in drinking-water. Therefore, it becomes important to prevent goitre through stopping the provision of iodised salt and providing normal drinking-water iodine through pipelines in these areas in China.     

碘与人群中甲状腺肿流行关系的观察

根据对山区、半山区、平原、沿海几个调查点四万人的甲状腺检查和尿碘、水碘的分析,揭示了从“低碘”、“中碘”到“高碘”地区的碘和人群中甲状腺肿流行的关系:①尿碘在50 μg/g肌酐,水碘在5 μg/l以下时,碘越少甲状腺肿流行率越高;②尿碘从50 μg/g肌酐,到400 μg/g肌酐,水碘从5 μg/l到40 μg/l,甲状腺肿流行率降到最低水平;③尿碘400 μg/g肌酐,水碘40 μg/l以上时,甲状腺肿 流行率又缓慢上升,所以水碘、尿碘含量和人群中甲状腺肿流行呈现底部较宽阔的“V”字形曲线的关系。本资料揭示尿碘400 μg/g肌酐,水碘40μg/l是人群中流行率最低水平的数值。当以甲状腺肿患病率3%做为判定地方性甲状腺肿的标准(1978年我国的地方性甲状腺肿防治工作标准)时,则尿碘的安全范围为50-1000 μg/g肌酐,水碘的安全范围为5-200 μg/l,低于或高于这个范围都可引起人群中甲状腺肿的流行。     

2018年天津市水源性高碘地区学龄儿童碘营养现况调查

目的 了解水源性高碘地区学龄儿童碘营养现状及甲状腺肿大情况,为开展高碘危害防治工作提供参考依据。方法 从水源性高碘地区5个街/镇中,选择2 207名学龄儿童作为调查对象,采集儿童尿样测定尿碘含量,检测儿童甲状腺容积。结果 调查地区水碘含量范围是100.4～175.1 μg/L,各街/镇水碘中位数差异有统计学意义（χ2 = 19.422,P = 0.001）。儿童尿碘中位数为215.96 μg/L（141.88～307.66 μg/L）,男童尿碘中位数高于女童（Z = -2.768,P = 0.006）,各街/镇儿童尿碘中位数差异有统计学意义（χ2 = 71.981,P＜0.001）。儿童甲状腺容积中位数为3.2 mL（2.5～4.1mL）,甲肿率为3.7%。各街/镇儿童甲状腺容积中位数差异有统计学意义（χ2 = 311.402,P＜0.001）,甲肿率差异无统计学意义（χ2 = 7.117,P = 0.130）。水碘与尿碘（rs = -0.037,P = 0.084）、甲状腺肿大（rs = - 0.022,P = 0.302）,尿碘与甲状腺肿大（rs = - 0.027,P = 0.209）之间相关性均无统计学意义。结论 本次调查研究暂未发现水碘、尿碘与甲状腺肿大之间的关联性。水源性高碘地区学龄儿童碘营养处于超足量水平,甲肿率高于我国多个省份,有关部门应当引起重视,因地制宜的制定防治方案。     

Age- and sex-adjusted iodine/creatinine ratio. A new standard in epidemiological surveys? Evaluation of three different estimates of iodine excretion based on casual urine samples and comparison to 24 h values

OBJECTIVE: The most accurate way to measure urinary iodine excretion in epidemiological surveys is still debated. We propose a new principle of estimating iodine excretion based on casual urine samples. MATERIAL AND METHODS: A total of 123 24 h urine samples and corresponding casual urine samples were collected from 31 subjects. Iodine excretion was expressed as 24 h iodine excretion and three different estimates: iodine concentration in the casual sample, iodine/gram creatinine in the casual sample, and the new principle-iodine/creatinine ratio in the casual sample, adjusted for expected creatinine excretion of the individual. RESULTS: All three estimates based on casual urine samples correlated significantly to 24 h values with a r (Pearson) of 0.37 for iodine concentration, 0. 61 for iodine/creatinine ratio and 0.62 for the age- and sex-adjusted iodine/creatinine ratio. The median iodine excretion in the entire group was 143 microg/day in 24 h samples, 87 microg/l as iodine concentration, 77 microg/g creatinine as iodine/creatinine ratio and 126 microg/day as age- and sex-adjusted iodine/creatinine ratio. CONCLUSION: Age- and sex-adjusted iodine/creatinine ratio is a more accurate and unbiased estimate of iodine excretion in epidemiological surveys of adults than the two most frequently used estimated: iodine concentration and iodine/gram creatinine, as these two estimates may introduce a bias depending on the composition of the investigated group. The adjusted iodine/creatinine ratio is superior to the other estimates, especially when individual estimates of 24 h iodine excretion is required or cohorts of selected groups are investigated. Sponsorship: This work was supported by grants from the Medical Research Foundation Region Greater Copenhagen, Faroe Islands and Greenland; the Wedell-Wedellsborg Foundation; Musikforlaeggerne Agnes and Knut Morks Foundation.     

Iodine intake of Japanese male university students: urinary iodine excretion of sedentary and physically active students and sweat iodine excretion during exercise

We examined the urinary iodine excretion of sedentary and physically active male university students in order to estimate the iodine intake of Japanese. Iodine excretion in sweat collected during treadmill exercise was also determined in different dietary iodine levels. The mean urinary iodine excretion of 5 sedentary students during 15 consecutive days was 357 micrograms/day (40-3,390). When high-iodine food, i.e. seaweed, was included in meals in only 22% of the total experimental days of 5 subjects, the urinary iodine excretion was high (1,106 micrograms/day, 298-3,390), but was low (153 micrograms/day, 40-441) when seaweeds were not consumed. An unexpectedly low mean urinary iodine excretion of 149 micrograms/day (50-393) was found in 10 rowing club students during 6 consecutive days of their summer training camp, probably being due to iodine losses in sweat; sweat iodine concentrations were about 37 micrograms per liter, regardless of serum and urinary iodine levels modulated by the dietary iodine level. The present data indicate that the iodine intake of Japanese depends on the amount of seaweed consumption and that it is not necessarily as high as expected from the data obtained in the 1960s. Moreover, our findings indicate the importance of taking account of iodine loss in sweat in the evaluation of iodine nutrition for physically active persons working in hot and humid environments.     

Determination of mercury in blood,urine and saliva for the biological monitoring of an exposure from amalgam fillings in a group with self-reported adverse health effects

It has been argued that the release of mercury from amalgam fillings is of toxicological relevance. The aim of the study was to determine the internal mercury exposure of two groups differing in their attitude towards possible health hazards by mercury from amalgam fillings. It was to be examined if the two groups differ with regard to the mercury concentration in different biological matrices and to compare the results with current reference values. Blood, urine and saliva samples were analyzed from 40 female subjects who claimed to suffer from serious health damage due to amalgam fillings ("amalgam sensitive subjects"). 43 female control subjects did not claim any association ("amalgam non-sensitive controls"). Mercury was determined by means of cold vapour atomic absorption spectrometry. Number and surfaces of amalgam fillings were determined by dentists for each subject. Median (range) mercury levels in blood were 2.35 (0.25-13.40) micrograms/l for "amalgam sensitive subjects" and 2.40 (0.25-10.50) micrograms/l for "amalgam non-sensitive controls". In urine, the median mercury concentrations were 1.55 (0.06-14.70) micrograms/l and 1.88 (0.20-8.43) micrograms/g creatinine respectively. No significant differences could be found between the two groups. Mercury levels in blood and urine of the examined subjects were within the range of background levels in the general population including persons with amalgam fillings. Stimulated saliva contained 76.4 (6.7-406.0) micrograms mercury/l in "amalgam sensitive subjects" and 57.0 (2.8-559.0) micrograms mercury/l in controls (not significant). Mercury levels in saliva did not correlate with the concentrations in blood and urine, but merely with the number of amalgam fillings or of the filling surfaces. Mercury in saliva is therefore not recommended for a biological monitoring.     

杭州市人群碘营养状况调查

目的了解和掌握杭州市人群碘营养现况,指导市民科学补碘,优化杭州市人群碘营养状况。方法在全市范围内12个区、县(市)各随机抽取3个调查点,各调查点随机抽取100户居民,采集家庭盐样及尿样进行盐碘和尿碘的检测。采用硫代硫酸钠法测定盐碘;酸消化砷-铈接触法检测尿碘。结果全市共检测盐碘3 604份,盐碘中位数为29.60mg/kg,碘盐覆盖率为95.73%,碘盐合格率为97.42%,合格碘盐食用率为93.26%;尿样12 805份,尿碘中位数为175.00μg/L,其中城区、郊区和农村尿碘中位数分别为162.00μg/L、168.00μg/L和194.81μg/L,农村高于城区及郊区(χ2=209.746 3,P<0.000 1);男性尿碘中位数为182.00μg/L高于女性的168.62μg/L(χ2=12.6402,P=0.005 5);8岁以下、8～10岁儿童、育龄妇女和成人尿碘中位数分别为189.13μg/L、174.73μg/L、177.54μg/L和174.00μg/L,8岁以下尿碘水平高于其他三组人群(χ2=12.640 2,P=0.0055)。结论目前杭州市人群碘营养总体处于适宜水平,随着本市碘缺乏病的趋向消除,继续保持并优化杭州市人群碘营养状况显得尤为重要。     

2013-2017年渭南市重点人群尿碘检测结果分析

目的 分析渭南地区重点人群的碘营养状况,为有针对性的防治碘缺乏病提供对策。方法 2013-2017年每年分别选取渭南市10个县的1所小学,从每所小学选取42名学生采集尿液测定尿碘;对抽中的街道/乡镇随机选取21名孕妇采集尿样测定尿碘。结果 2013-2017年 共计检测儿童7 400份尿样,尿碘中位数是269.4 μg/L,儿童尿碘小于100 μg/L的样本占检测总数的10.0％,尿碘大于100 μg/L的样本占检测总数的90.0％,其中尿碘大于300 μg/L的样本占检测总数的38.3%;共计检测孕妇4 300份尿样,尿碘中位数是 219.6μg/L,孕妇尿碘小于150 μg/L的样本占检测总数的35.6%,尿碘大于150 μg/L的样本占检测总数的64.4%,其中尿碘大于500 μg/L的样本占检测总数的8.6%。结论 渭南市10个县市区儿童人群碘营养水平总体仍处于超适量摄入状态,特需人群碘营养水平总体处于适宜状态,孕妇碘摄入量可以满足人体需要,碘营养状况良好。     

江苏省高水碘地区学龄儿童碘营养状况调查

目的:了解江苏省高水碘地区8～10岁学龄儿童的碘营养状况。方法:在江苏省徐州市的丰县、沛县、铜山县、睢宁县、邳州市和淮安市的楚州区6个存在高水碘乡镇的县(市、区),每个县(市、区)用随机抽样的方法抽取5个高水碘乡(镇),不足5 h全部抽取,每个乡(镇)随机抽取1所小学,在每所小学随机抽取20名8～10岁学龄儿童作为调查对象。用砷、铈催化分光光度法检测尿样中碘含量,用盐碘半定量检测方法检测其所在居民户食用盐盐样。结果:已停供碘盐地区,非碘盐覆盖率为98.2%;共检测儿童尿样600份,总的尿碘中位数为452.7μg/L,停供碘盐和未停供碘盐地区尿碘中位数分别为538μg/L和231.5μg/L,两者比较差异有统计学意义(P<0.05)。结论:高水碘地区应进一步开展居民饮用水水碘含量调查,慎重对待部分地区的停供碘盐措施,对于儿童碘营养严重过剩的地区,不仅仅要停供碘盐,还要改水降碘。     

Ten repeat collections for urinary iodine from spot samples or 24-hour samples are needed to reliably estimate individual iodine status in women

Although the median urinary iodine concentration (UIC) is a good indicator of iodine status in populations, there is no established biomarker for individual iodine status. If the UIC were to be used to assess individuals, it is unclear how many repeat urine collections would be needed and if the collections should be spot samples or 24-h samples. In a prospective, longitudinal, 15-mo study, healthy Swiss women (n = 22) aged 52-77 y collected repeated 24-h urine samples (total n = 341) and corresponding fasting, second-void, morning spot urine samples (n = 177). From the UIC in spot samples, 24-h urinary iodine excretion (UIE) was extrapolated based on the age- and sex-adjusted iodine:creatinine ratio. Measured UIE in 24-h samples, estimated 24-h UIE, and UIC in spot samples were (geometric mean ± SD) 103 ± 28 μg/24 h, 86 ± 33 μg/24 h, and 68 ± 28 μg/L, respectively, with no seasonal differences. Intra-individual variation (mean CV) was comparable for measured UIE (32%) and estimated UIE (33%). The CV tended to be higher for the spot UIC (38%) than for the estimated 24-h UIE (33%) (P = 0.12). In this population, 10 spot urine samples or 24-h urine samples were needed to assess individual iodine status with 20% precision. Spot samples would likely be preferable because of their ease of collection. However, the large number of repeated urine samples needed to estimate individual iodine status is a major limitation and emphasizes the need for further investigation of more practical biomarkers of individual iodine status.     

Cadmium concentrations in hair, urine and blood among residents in a cadmium-polluted area, Nagasaki, Japan: a 18-year follow-up after soil replacement]

In 1981, the soil of cadmium (Cd)-polluted rice fields was replaced with new soil in Kashine, a Cd-polluted district located on Tsushima Island, Nagasaki Prefecture, Japan. Consequently, the average dietary Cd intake among the inhabitants decreased from 215 micrograms/day in 1969 to 106 micrograms/day in 1983. The authors investigated the health status of Kashine inhabitants before and after the reduction of Cd intake. Concentrations of beta 2-microglobulin in urine (U-beta 2-mg) and Cd in urine (U-Cd), hair (H-Cd) and blood (B-Cd) were measured on 35 inhabitants in 1979 and 1996. The geometric mean of U-beta 2-mg concentration for 9 subjects with U-beta 2-mg levels > or = 1,000 micrograms/g creatinine (microgram/g cr) in 1979 increased by approximately 2.5-fold in 1996. Meanwhile there was little change in the geometric mean for 26 subjects with U-beta 2-mg levels < 1,000 micrograms/g cr in 1996. It was concluded that renal tubular dysfunction among Cd-exposed inhabitants was irreversible and progressive, even after dietary Cd intake decreased. The geometric mean of U-Cd concentration decreased significantly from 11.0 micrograms/g cr in 1979 to 6.3 micrograms/g cr in 1996. The decrease in U-Cd concentrations was significantly greater among inhabitants with U-beta 2-mg levels > or = 1,000 micrograms/g cr than among those with U-beta 2-mg levels < 1,000 micrograms/g cr (p = 0.03). From these results, it was considered that the level of U-Cd was more decreased by the presence of renal tubular dysfunction. The geometric mean of H-Cd concentration decreased significantly from 109.1 micrograms/kg in 1979 to 55.1 micrograms/kg in 1996. However, it was unclear whether the decrease of H-Cd depended on the decrease of dietary Cd intake, decrease of body burden or both, because U-Cd concentrations also decreased by approximately 43% during this period. H-Cd concentration was weakly and positively correlated with U-Cd (r = 0.38-0.44), an indicator of body burden of Cd. These results suggested that H-Cd concentration was influenced by the body burden of this metal. The geometric mean of B-Cd concentration in 33 inhabitants was 5.7 micrograms/l in 1996. The geometric mean was significantly greater in subjects with initial U-beta 2-mg levels > or = 1,000 micrograms/g cr than in those with U-beta 2-mg levels < 1,000 micrograms/g cr. A close positive correlation was found between B-Cd concentrations and U-Cd (r = 0.70, p < 0.01). It was suggested that the body burden influenced the levels of B-Cd as well as U-Cd, many years after Cd exposure had decreased.     

2017年郴州市生活饮用水水碘含量调查结果分析

目的 全面了解郴州市生活饮用水水碘含量,科学指导碘缺乏病防治工作。 方法 按照《全国生活饮用水水碘含量调查方案》要求,对11个县(市、区)158个乡(镇、街道)开展以乡镇为单位的饮用水水碘含量调查,水碘中位数大于10 μg/L的乡镇开展以行政村(居委会)为单位的生活饮用水水碘调查。采用国家碘缺乏病参照实验室推荐方法检测水碘含量。采用Excel 2007和SPSS 17.0软件分析水碘调查数据。 结果 11个县(市、区)158个乡(镇、街道)共采集水样1 319份,水碘含量＜10 μg/L的水样占89.92%(1 186/1 319)。11个县(市、区)水碘中位数均＜10 μg/L;158个乡镇中,水碘中位数＜10 μg/L的占98.73%(156/158),10~100 μg/L的占1.27%(2/158)。以行政村为单位调查,共调查2个县2个乡镇19个村,水碘中位数＜10 μg/L的村占57.89%(11/19),10~100 μg/L的村占42.11%(8/19)。集中供水、部分集中供水和分散式供水水碘中位数分别为2.76、2.01和1.62 μg/L,总体差异有统计学意义(H=17.94,P<0.001),集中供水水碘中位值显著高于部分集中供水(D=11.19,P=0.000)和分散式供水(D=16.97,P=0.000)。地表水和井水水碘中位数分别为1.50和2.54 μg/L,差异有统计学意义(Z=-9.55,P<0.001)。城市地区和农村地区水碘中位数分别为3.37和1.90 μg/L,差异有统计学意义(Z=-2.68,P=0.007)。 结论 郴州市生活饮用水水碘含量总体处于较低水平,属外环境碘缺乏地区,须坚持科学补碘,持续开展碘缺乏病全面监测。