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.     

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.     

An evaluation of salt intake and iodine nutrition in a rural and urban area of the C?te d'Ivoire.

OBJECTIVE: To evaluate the habitual salt intake of individuals living in the C?te d'Ivoire, and to monitor the iodine nutrition of adults, schoolchildren and pregnant women one year after implementation of a universal salt iodisation programme. DESIGN: A three day weighed food records with estimation of food intake from a shared bowl based on changes on body weight, determination of sodium and iodine concentrations in 24 h (24 h) urine samples from adults, and determination of urinary iodine in spot urines from schoolchildren and pregnant women. SETTING: A large coastal city (Abidjan) and a cluster of inland villages in the northern savannah region of the C?te d'Ivoire. SUBJECTS: For the food records: 188 subjects (children and adults) in the northern villages; for the 24 h urine collections: 52 adults in Abidjan and 51 adults in the northern villages; for the spot urine collections: 110 children and 72 pregnant women in Abidjan and 104 children and 66 pregnant women in the north. MAIN RESULTS: From the food survey data in the north, the total mean salt intake (s.d.) of all age groups and the adults was estimated to be 5.7 g/d (+/- 3.0), and 6.8 g/d (+/- 3.2), respectively. In the 24 h urine samples from adults, the mean sodium excretion was 2.9 g/d (+/- 1.9) in the north and 3.0 g/d (+/- 1.3) in Abidjan, corresponding to an intake of 7.3-7.5 g/d of sodium chloride. In the north the median 24 h urinary iodine excretion in adults was 163 microg/d, and the median urinary iodine in spot urines from children and pregnant women was 263 microg/l and 133 microg/l, respectively. In contrast, in Abidjan the median 24 h urinary iodine was 442 microg/d, with 40% of the subjects excreting > 500 microg/d, and the median urinary iodine in spot urines from children and pregnant women was 488 microg/l and 364 microg/l, respectively. Nearly half of the children in Abidjan and 32% of the pregnant women were excreting > 500 microg/l. CONCLUSION: Based on the estimates of salt intake in this study, an optimal iodine level for salt (at the point of consumption) would be 30 ppm. Therefore the current goals for the iodised salt programme--30-50 ppm iodine appear to be appropriate. However, in adults, children and pregnant women from Abidjan, high urinary iodine levels--levels potentially associated with increased risk of iodine-induced hyperthyroidism--are common. These results suggest an urgent need for improved monitoring and surveillance of the current salt iodisation programme in the C?te d'Ivoire.     

Formulas developed based on the ratio of urea nitrogen to creatinine concentrations obtained from multiple spot urine samples are acceptable to predict protein intake at group level but not at individual level

In this study, we hypothesized that spot urine can be used to predict protein intake at both group and individual levels. Participants (n = 369) of this study were recruited from all 47 prefectures in Japan. Sex-specific formulas were developed based on the ratio of urea nitrogen to creatinine concentration obtained from 3 spot urine samples. Validity of the formulas was examined against two 24-hour urine collections for 7 combinations of spot urine (single and means of 2 or 3 samples) using t test (mean estimation), Spearman correlation, and Bland-Altman plot (individual bias). Means of measured protein intake based on 24-hour urinary excretions were 87.3 g/d (standard deviation 19.7) for men and 70.5 g/d (standard deviation 14.7) for women. Irrespective of sex, the predicted intakes were not significantly different (within 2.7% of differences) from those measured by urinary excretions. Predicted intakes were moderately correlated with measured intakes (men, 0.45-0.60; women, 0.35-0.53). Even after using the mean of 3 samples, Bland-Altman plots showed a considerably wide limit of agreement (men, −30 to 33 g/d; women, −27 to 24 g/d). Except for using single spot urine samples in women, the formula tended to overestimate intake at a lower and underestimate at a higher level of protein intake (slope: men, −0.47 [P < .0001]; women, −0.38 [P = .002]). In conclusion, predictive formulas developed in this study can be used to predict protein intake at group level or to rank individuals' intake but not to predict absolute intake at individual level.     

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.     

Evaluation of take-home organophosphorus pesticide exposure among agricultural workers and their children

We analyzed organophosphorus pesticide exposure in 218 farm worker households in agricultural communities in Washington State to investigate the take-home pathway of pesticide exposure and to establish baseline exposure levels for a community intervention project. House dust samples (n = 156) were collected from within the homes, and vehicle dust samples (n = 190) were collected from the vehicles used by the farm workers to commute to and from work. Urine samples were obtained from a farm worker (n = 213) and a young child (n = 211) in each household. Dust samples were analyzed for six pesticides, and urine samples were analyzed for five dialkylphosphate (DAP) metabolites. Azinphosmethyl was detected in higher concentrations (p < 0.0001) than the other pesticides: geometric mean concentrations of azinphosmethyl were 0.53 micro g/g in house dust and 0.75 micro g/g in vehicle dust. Dimethyl DAP metabolite concentrations were higher than diethyl DAP metabolite concentrations in both child and adult urine (p < 0.0001). Geometric mean dimethyl DAP concentrations were 0.13 micro mol/L in adult urine and 0.09 micro mol/L in child urine. Creatinine-adjusted geometric mean dimethyl DAP concentrations were 0.09 micro mol/g in adult urine and 0.14 micro mol/g in child urine. Azinphosmethyl concentrations in house dust and vehicle dust from the same household were significantly associated (r2 = 0.41, p < 0.0001). Dimethyl DAP levels in child and adult urine from the same household were also significantly associated (r2 = 0.18, p < 0.0001), and this association remained when the values were creatinine adjusted. The results of this work support the hypothesis that the take-home exposure pathway contributes to residential pesticide contamination in agricultural homes where young children are present.     

Naturally occurring iodine in humic substances in drinking water in Denmark is bioavailable and determines population iodine intake

Iodine intake is important for thyroid function. Iodine content of natural waters is high in some areas and occurs bound in humic substances. Tap water is a major dietary source but bioavailability of organically bound iodine may be impaired. The objective was to assess if naturally occurring iodine bound in humic substances is bioavailable. Tap water was collected at Randers and Skagen waterworks and spot urine samples were collected from 430 long-term Randers and Skagen dwellers, who filled in a questionnaire. Tap water contained 2 microg/l elemental iodine in Randers and 140 microg/l iodine bound in humic substances in Skagen. Median (25; 75 percentile) urinary iodine excretion among Randers and Skagen dwellers not using iodine-containing supplements was 50 (37; 83) microg/24 h and 177 (137; 219) microg/24 h respectively (P < 0.001). The fraction of samples with iodine below 100 microg/24 h was 85.0 % in Randers and 6.5 % in Skagen (P < 0.001). Use of iodine-containing supplements increased urinary iodine by 60 microg/24 h (P < 0.001). This decreased the number of samples with iodine below 100 microg/24 h to 67.3 % and 5.0 % respectively, but increased the number of samples with iodine above 300 microg/24 h to 2.4 % and 16.1 %. Bioavailability of iodine in humic substances in Skagen tap water was about 85 %. Iodine in natural waters may be elemental or found in humic substances. The fraction available suggests an importance of drinking water supply for population iodine intake, although this may not be adequate to estimate population iodine intake.     

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。     

Status of iodine nutrition in pregnant and lactating women in national capital district, Papua New Guinea

Urinary Iodine excretion is a useful and important indicator of the iodine status of a population. This study attempts to determine the urinary iodine concentration of non-pregnant, pregnant and lactating women, resident in the National Capital District of Papua New Guinea, so as to evaluate their status of iodine nutrition. The study population was made up of 56 non-pregnant, 40 lactating and 212 pregnant women. Of the 212 pregnant women, 14 were in the first, 64 in the second, and 134 in the third Trimester of pregnancy. Casual urine samples were collected and analysed for urinary iodine by Sandell-Kolthoff reaction. The median urinary iodine concentration for the non-pregnant, lactating and pregnant women was 163.0 micro g/L, 134.0 micro g/L and 180.0 micro g/L, respectively. Median urinary iodine for the first, second and third trimesters were 165.0 micro g/L, 221.5 micro g/L and 178.0 micro g/L, respectively. The 20th percentile urinary iodine values were higher than 50 micro g/L for all the groups. This indicates adequate intake of dietary iodine and optimal status of iodine nutrition amongst women in the various groups. Mild to severe status of iodine nutrition was found in 30.4% of non-pregnant, 35.0% of lactating, 22.2% of pregnant women, 28.5% of women in the first, 18.8% in the second, and 23.1% in the third trimester of pregnancy. To achieve optimal iodine nutrition in pregnant and lactating women, an increase in their intake of dietary iodine is recommended.     

Nationwide Representative Survey of Dietary Iodine Intake and Urinary Excretion in Postpartum Korean Women

Iodine is an essential component of thyroid hormones, but excessive iodine intake can lead to thyroid dysfunction. Traditionally, Korean mothers consume brown seaweed soup (miyeokguk), a high source of iodine, after childbirth. There is controversy regarding the effects of excessive postpartum iodine intake on the health of mothers and infants. Thus far, there have been no nationwide large-scale surveys regarding the status of iodine intake among postpartum women in Korea. Therefore, we conducted a nationwide survey of postpartum dietary iodine intake among Korean women. In total, 1054 Korean women aged ≥19 years, at less than 8 weeks postpartum, participated in this survey. Dietary data were collected using self-reported 2-day dietary records, along with before-and-after meal photos. To evaluate the correlation between dietary iodine and urinary iodine excretion (UIE), spot urine, and 24 h urine samples were collected from 98 and 29 participants, respectively. The mean daily iodine intake among all participants was 2945.6 μg, and it gradually decreased over time after childbirth. Dietary iodine intake was significantly correlated with 24 h UIE (r = 0.396, p < 0.05) and spot urine UIE (r = 0.312, p < 0.05). Follow-up studies are required to examine the influence of excessive postpartum iodine intake on thyroid health in mothers and their infants.     

Urinary creatinine concentrations in an industrial workforce and comparison with reference values of the general population

Purpose

Urinary creatinine is an important parameter for the adjustment of metabolite concentrations in differently diluted urine specimens, as a reference dimension for biological limit or guidance values and as a selection criterion for spot urine samples in human biomonitoring. While the creatinine output of the general population has been well described in environmental surveys, this study focused specifically on creatinine concentrations in a large industrial workforce in order to compare these data with the general population and to provide a database for the calculation of a reasonable conversion factor between volume-related and creatinine-adjusted data and vice versa.

Methods

Urinary creatinine was analysed in 6,438 spot urine samples by a photometric assay in the time period between 1989 and 2009. Basic demographic data (age, sex, body weight, body height) and job category (apprentices, skilled craftsmen, skilled chemical workers, foremen, laboratory staff and executives) were considered in a statistical analysis.

Results

The median concentration of urinary creatinine in all urine samples was 1.36 g/L with male employees showing significantly higher values (1.37 g/L, n = 6,148 samples) than female employees (1.00 g/L, n = 290) and concentrations ranging from 0.01 up to 9.76 g/L. Age, body mass index and job category were significant influence factors on urinary creatinine. About 92 % of all samples showed creatinine concentrations between 0.3 and 3.0 g/L, a range recommended by the World Health Organization as a criterion for valid spot urine samples.

Discussion

The results of this study correspond well with data from environmental surveys and with recent data from an active workforce in industry with similar sampling strategies. Therefore, a median of 1.4 g creatinine per litre urine seems to be a reasonable value for general calculations and adjustments. The study data also support the validity of the current recommendations by the WHO and several scientific committees and institutions with respect to creatinine limits in spot urine samples for occupational-medical biomonitoring.     

尿中肌酐排泄稳定性的研究

分析在自由饮水条件下７７３个健康人的一次点尿样，６２人的２４ｈ尿样及８人连续５天收集的２４ｈ尿样，对这些尿样分别测定比重、肌酐浓度及肌酐排泄量，以揭示尿肌酐排泄的稳定性。研究发现，尿肌酐浓度与尿比重之间具有一定的相关性，尿肌酐排泄存在明显的个性差异和体内变异。可以认为，肌酐排泄的稳定性较差，用肌酐作为尿毒物浓度的校正参数，其适合性和可靠性值得怀疑。     

江苏省某县两岁幼儿双酚A暴露水平评估及影响因素分析

目的 评估2岁幼儿尿中双酚A(bisphenol A,BPA)水平和每日摄入量及其影响因素,为进一步研究BPA对幼儿健康影响提供基础数据。方法 选取某县365名幼儿,由其父母完成问卷调查并协助幼儿采集尿样,测定尿中BPA含量,估算每日摄入量及分析影响因素。结果 BPA检出率为72.05%,可检出浓度范围为0.20～106.38 μg/L,肌酐未校正和校正后中位值分别为0.95 μg/L和2.96 μg/g。每日摄入量按肌酐估算最大值为4.596 μg/kg bw/24 h,低于欧盟食品安全机构(European Food Safety Authority,EFSA)提出的BPA每日允许摄入量(tolerable daily intake,TDI)。统计分析结果显示不同性别幼儿BPA水平相似,而不同居住地间BPA水平差异有统计学意义(P<0.05)。结论 该地区2岁幼儿普遍暴露于BPA,暴露水平低于EFSA提出的TDI。     

福建省2009年8～10岁儿童碘营养评估

目的了解福建省儿童碘营养水平,为因地制宜、科学补碘提供依据。方法全省84个县(市、区)按5个方位随机抽取1所村小学,每所小学各随机抽检20名8～10岁儿童检测尿碘含量。结果全省共检测尿样8 218份,尿碘中位数为184.1μg/L,尿碘水平<50μg/L的占5.1%。沿海地区儿童尿碘中位数(157.7μg/L)小于内陆地区(201.1μg/L)。结论福建省儿童碘营养总体上处于适宜水平,碘营养水平主要与碘盐摄入量有关,与是否处于沿海地区无关。     

碘摄入量与晨尿中碘排量的关系研究

目的研究晨尿的尿碘含量及其肌酐校正的每日尿排碘量与碘摄入量的相关关系,探讨准确反映机体碘摄入量的指标。方法将经筛选的161名志愿者随机分为500～2000μg/d的7个剂量组中。采用7d膳食记录法计算膳食碘摄入量。在给与碘补充剂后第0、2、4w取空腹晨尿,分别以砷铈催化分光光度法和碱性苦味酸法测定尿碘含量和尿肌酐含量,并计算出肌酐校正的每日尿排碘量。对各组晨尿碘含量和每日尿排碘量进行方差分析,并与碘摄入量进行回归分析。结果膳食中碘的摄入量在各剂量组间没有显著性差异,均值为328μg/d。给碘补充剂前晨尿碘含量和肌酐校正的每日尿排碘量在各剂量组间均没有显著性差异(P>0.05),均值分别为325μg/L和314μg/d。而给碘补充剂后第2、4w晨尿碘含量和肌酐校正的每日尿排碘量随剂量的增加而增加,在各剂量组间均有显著性差异(P<0.05)。回归分析显示其相关系数在0.958～0.976之间(P=0.000),肌酐校正的每日尿排碘量与碘摄入量回归方程的斜率接近1。结论晨尿的尿碘含量及肌酐校正的每日尿排碘量都是表述机体碘摄入量的敏感指标。因晨尿尿碘含量易受干扰而波动,只适用于大样本群体的碘营养状况调查。晨尿经肌酐校正的每日尿排碘量相对比较稳定,能更准确地反映碘的摄入量,既适用于群体,也适用于个体的碘营养状况评价。     

2010年广元市5县区学龄儿童尿碘检测结果分析

目的了解广元市5个县区8 10岁小学生碘营养状况,为碘缺乏病防治工作提供科学依据。方法对广元市5个县区小学497名学生采集尿液,用W S/T107-2006砷铈催化分光光度法测定尿碘。结果 5个县区共检测尿样497份,其尿碘中位数为336.90μg/L,各县区未检出尿碘20μg/L的样本,尿碘50μg/L的样本占0.60%,尿碘100μg/L的样本占检测总数的94.57%,其中尿碘300μg/L的样本占检测总数的57.55%。结论广元市5个县区学龄儿童碘摄入量可以满足人体需要碘营养状况良好,但仍需继续做好合格碘盐的供应和监测,同时应该密切关注学龄儿童碘摄入量,防止补碘过量,开展健康教育。     

青海省不同地区人群膳食摄碘水平调查

目的:调查青海省不同地区人群膳食碘摄入量,为科学补碘、持续消除碘缺乏危害提供依据。方法:2018-2019年,依据青海省行政区划、自然地理区划、人口分布和经济发展水平,共抽取14个调查点,每个调查点抽取1个村,每个村抽取20户世居者,采集每户家庭盐样、每个家庭成员24 h尿样,检测盐碘、尿碘;在每个村按东、西、南、北、...     

2011年四川省碘缺乏病监测结果分析

目的掌握四川省碘缺乏病病情、居民碘营养水平及防治措施落实情况,为制订防治措施提供科学依据。方法按＂人口比例概率抽样方法＂（PPS）在全省抽取30个县,每个县抽取1所小学;每个小学抽查40名8～10岁儿童甲状腺容积,并定量检测其家中食用盐碘含量;抽取其中12名儿童检测尿碘,并调查其家中居民人均日盐摄入量;在抽中学校附近选择3个乡（镇、街道办）,每个乡（镇、街道办）抽取孕妇和哺乳妇女各5人检测尿碘;在抽中学校的所在村（居委会）,按东、西、南、北、中各抽取1份饮用水水样,如为集中式供水地区,则采集2份末梢水样检测水碘。全省在上述PPS法未抽到的152个县中,每县按东、西、南、北、中5个方位各抽取1个乡（镇、街道）,每个乡（镇、街道）抽取1所小学,每所小学抽检20名8～10岁儿童（男、女各半）尿碘。结果 B超法检查儿童1 221人,甲状腺肿大率4.1%;检测盐样1 206份,合格碘盐食用率98.1%,碘盐覆盖率99.9%,碘盐合格率98.2%,盐碘中位数32.8 mg/kg;检测儿童尿碘15393份,尿碘中位数208.9μg/L,其中男性儿童尿碘中位数（214.9μg/L）高于女性（203.2μg/L,Z=6.97,P〈0.05）;孕妇尿碘457份,尿碘中位数170.8μg/L;哺乳妇女尿碘452份,尿碘中位数159.5μg/L;水碘81份,水碘中位数2.7μg/L,范围0.2～49.6μg/L,水碘低于10μg/L比例为82.7%（67/81）;调查363户家庭食盐摄入量,人均日摄盐量8.46 g。结论四川自然环境普遍缺碘;人群碘营养水平总体适宜,继续保持消除碘缺乏病状态。     

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。