Intake of thiocyanate by way of milk and its possible effect on thyroid function

The keeping quality of milk can be improved if the lactoperoxidase system is activated. To make such an activation efficient the thiocyanate concentration has to be increased. Since, however, thiocyanate has a potent antithyroid effect, thyroid function has been studied in 37 healthy individuals during 12 wk of daily intake of 8 mg thiocyanate by way of milk. The thiocyanate increased significantly in serum and reached a maximum value after 4 wk (+3.8 mg/1). The increased serum levels coincided with an increased excretion in urine (+ 4.8 mg/g creatinine). The levels of thyroxine, triiodothyronine, and thyrotropic hormone were all in the normal range at the beginning of the investigation and no significant changes were found during the experimental period. In conclusion, a daily intake of 8 mg thiocyanate by way of milk does not have any apparent effect on the thyroid function.     

Effect of oral iodized oil on thyroid size and thyroid hormone metabolism in children with concurrent selenium and iodine deficiency

OBJECTIVES: To determine the efficacy of oral iodized oil in goitrous children who are both selenium (Se) and iodine deficient; to investigate if Se status modifies the response of iodine deficient, goitrous children to oral supplementation with iodized oil. DESIGN: A longitudinal intervention trial. SETTING: Two rural villages in the western C?te d'Ivoire. SUBJECTS: 51 goitrous non-anemic schoolchildren with both iodine and Se deficiency. INTERVENTION: Each child received an oral dose of 0.4 ml iodized poppyseed oil containing 200 mg of iodine. They were followed for 1 y with measurements of urinary iodine (UI), thyrotropin (TSH), thyroxine (T4), and thyroid volume by ultrasound. RESULTS: At baseline all children were goitrous and Se deficient; median UI was 29 microg/l and mean serum Se (s.d.) was 14.8 (10.7) microg/l. After receiving iodized oil, thyroid volume decreased significantly vs baseline at 10, 15, 30 and 50 weeks (P<0.001). At 50 weeks mean percentage change in thyroid volume from baseline was-46.6% and only five children remained goitrous. Median TSH values at 5, 10, 15, 30 and 50 weeks were reduced significantly (P<0.001) compared to baseline. Among individual children the severity of Se deficiency predicted the degree of response to iodized oil. Baseline serum Se and percentage change in thyroid volume from baseline at 50 weeks were strongly correlated (r2=0.554). Baseline Se and percentage decrease in TSH from baseline at 30 weeks were also well-correlated (r2=0.467). CONCLUSION: Although more severe Se deficiency partially blunts the thyroid response to iodine supplementation, oral iodized oil is an effective method for iodine repletion in goitrous children who are Se deficient. SPONSORSHIP: The Swiss Federal Institute of Technology, Zürich, the Foundation for Micronutrients in Medicine, Rapperswil, Switzerland, and the Thrasher Research Fund, Salt Lake City, USA.     

Seaweed and soy: companion foods in Asian cuisine and their effects on thyroid function in American women

Seaweeds and soy are two commonly eaten foods in Asia. Both have been reported to affect thyroid function, seaweed because of its iodine content and soy because of its goitrogenic effect. Twenty-five healthy postmenopausal women (mean age 58 years) completed a double-blinded randomized crossover study. Ten capsules (5 g/day) of placebo or seaweed (Alaria esculenta), providing 475 microg of iodine/day, were consumed daily for 7 weeks. A powdered soy protein isolate (Solae Co., St. Louis, MO), providing 2 mg of isoflavones/kg of body weight, was given daily during the last week of each treatment arm. On average, this provided 141.3 mg of isoflavones/day and 67.5 g of protein/day. Blood samples and 48-hour urine samples were collected before and after each intervention period, and urinary I/C (microg of iodine/g of creatinine) and serum thyroxine, free thyroxine index, total triiodothyronine, and thyroid stimulating hormone (TSH) were measured. Seaweed ingestion increased I/C concentrations (P < .0001) and serum TSH (P < .0001) (1.69 +/- 0.22 vs. 2.19 +/- 0.22 microU/mL, mean +/- SE). Soy supplementation did not affect thyroid end points. Seven weeks of 5 g/day seaweed supplementation was associated with a small but statistically significant increase in TSH. Soy protein isolate supplementation was not associated with changes in serum thyroid hormone concentrations.     

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.     

Prolonged high iodine intake is associated with inhibition of type 2 deiodinase activity in pituitary and elevation of serum thyrotropin levels

Our previous epidemiological study indicated that excessive intake of iodine could potentially lead to hypothyroidism. In the present study, we aimed to investigate the time and dose effect of iodine intake on serum thyrotropin (thyroid-stimulating hormone, TSH) levels and to explore the non-autoimmune regulation of serum TSH by pituitary type 2 deiodinase (D2). A total of 360 Wistar rats were randomly divided into five groups depending on administered iodine dosages (folds of physiological dose): normal iodine (NI), 3-fold iodine (3HI), 6-fold iodine (6HI), 10-fold iodine (10HI) and 50-fold iodine (50HI). At 4, 8, 12 and 24 weeks after administration of sodium iodide, blood was collected for serum TSH measurement by chemiluminescent immunoassay. Pituitaries were also excised for measurement of TSHβ subunit expression, D2 expression and activity, monocarboxylate transporter 8 (MCT8) and thyroid hormone receptor β2 isoform (TRβ2) levels. The results showed that iodine intake of 10HI and 50HI significantly increased pituitary and serum TSH levels from 8 to 24 weeks (P?相似文献   

Iodine Status and Thyroid Function in a Group of Seaweed Consumers in Norway

Seaweeds, or macroalgae, may be a good dietary iodine source but also a source of excessive iodine intake. The main aim in this study was to describe the iodine status and thyroid function in a group of macroalgae consumers. Two urine samples were collected from each participant (n = 44) to measure urinary iodine concentration (UIC) after habitual consumption of seaweed. Serum thyroid stimulating hormone (TSH), free thyroxine (fT₄), free triiodothyronine (fT₃), and peroxidase autoantibody (TPOAb), were measured in a subgroup (n = 19). A food frequency questionnaire and an iodine-specific 24 h recall were used to assess iodine intake and macroalgae consumption. The median (p25–p75) UIC was 1200 (370–2850) μg/L. Median (p25–p75) estimated dietary iodine intake, excluding macroalgae, was 110 (78–680) μg/day, indicating that seaweed was the major contributor to the iodine intake. TSH levels were within the reference values, but higher than in other comparable population groups. One third of the participants used seaweeds daily, and sugar kelp, winged kelp, dulse and laver were the most common species. Labelling of iodine content was lacking for a large share of the products consumed. This study found excessive iodine status in macroalgae consumers after intake of dietary seaweeds. Including macroalgae in the diet may give excessive iodine exposure, and consumers should be made aware of the risk associated with inclusion of macroalgae in their diet.     

Relations between various measures of iodine intake and thyroid volume,thyroid nodularity,and serum thyroglobulin

BACKGROUND: Iodine intake can be measured in various ways, and each method may have advantages and disadvantages. OBJECTIVE: We sought to investigate the potential associations of various measures of iodine intake with thyroid volume, prevalence of thyroid nodules, and serum thyroglobulin. We also sought to identify, if possible, groups at risk of thyroid disease because of their food choices. DESIGN: This cohort study included 4649 randomly selected subjects with mild-to-moderate iodine deficiency; the subjects lived in 2 cities in Denmark. Iodine intake was estimated by using a food-frequency questionnaire and by measuring iodine excretion in spot urine samples. Thyroid volume and nodularity were measured with ultrasonography. RESULTS: In multiple linear regression models, significant inverse relations were found between thyroid volume and estimated 24-h iodine excretion, iodine intake from diet plus supplements, iodine intake from diet/kg body wt, and milk intake (P = 0.001 for all), but not urinary iodine excretion measured as a concentration (P = 0.40). All measures of iodine intake were significantly related to serum thyroglobulin concentration (P 相似文献   

Impact of smoking and thiocyanate on perchlorate and thyroid hormone associations in the 2001-2002 national health and nutrition examination survey

BACKGROUND: Findings from a recent large study suggest that perchlorate at commonly occurring exposure concentrations may decrease thyroid hormone levels in some women. Decreases in thyroid hormone seen with perchlorate exposure could be even greater in people with concomitant exposure to agents such as thiocyanate that may affect the thyroid by mechanisms similar to those of perchlorate. OBJECTIVES AND METHODS: We used data from the National Health and Nutrition Examination Survey to assess the impact of smoking and thiocyanate on the relationship between urinary per-chlorate and serum thyroxine (T(4)) and thyroid-stimulating hormone (TSH). RESULTS: In women with urinary iodine levels < 100 microg/L, the association between the logarithm of perchlorate and decreased T(4) was greater in smokers [regression coefficient (beta) = -1.66, p = 0.0005] than in nonsmokers (beta = -0.54, p = 0.04). In subjects with high, medium, and low cotinine levels, these regression coefficients were -1.47 (p = 0.0002), -0.57 (p = 0.03), and -0.16 (p = 0.59). For high, medium, and low thiocyanate tertiles they were -1.67 (p = 0.0009), -0.68 (p = 0.09), and -0.49 (p = 0.11). Clear interactions between perchlorate and smoking were not seen with TSH or with T(4) in women with urinary iodine levels > or = 100 microg/L or in men. CONCLUSIONS: These results suggest that thiocyanate in tobacco smoke and perchlorate interact in affecting thyroid function, and this effect can take place at commonly occurring perchlorate exposures. Agents other than tobacco smoke might cause similar interactions, and further research on these agents could help identify people who are particularly susceptible to perchlorate.     

Monitoring the adequacy of salt iodization in Switzerland: a national study of school children and pregnant women

BACKGROUND: Several countries with long-standing salt iodization programs, including Switzerland, have recently reported declining and/or low urinary iodine (UI) levels in their populations. In Switzerland, in response to studies indicating low UI levels in children and pregnant women, the salt iodine level was increased in 1998 from 15 to 20 mg/kg. OBJECTIVE: Our objective was to evaluate iodine nutrition in a national sample of Swiss school children and pregnant women 8 16 months after the increase in the salt iodine level. DESIGN: A 3-stage probability proportionate to size cluster sampling method was used to obtain a representative national sample of 600 children aged 6-12 y and 600 pregnant women. We then measured UI in both groups, thyrotropin (TSH) in pregnant women and thyroid volume by ultrasound to determine goiter prevalence in school children. RESULTS: The median UI (range) of the children and pregnant women was 115 microg/l (5-413) and 138 microg/l (5-1881), respectively. The median blood TSH concentration (range) of pregnant women was 0.6 mU/l (0.2-2.1). Based on the current WHO/ICCIDD normative data for thyroid volume, none of the children were goitrous, using either age/sex-specific or BSA/sex-specific cutoffs. CONCLUSIONS: The iodine status of the Swiss population is once again adequate, illustrating the value of periodic monitoring and prudent adjustments to the iodine level in salt. This approach could serve as a model for countries struggling to maintain dietary iodine intake in the face of shifting dietary habits and changes in the food supply.     

Iodine concentration in Norwegian milk and dairy products

The present study was conducted to determine the iodine concentration in Norwegian-produced milk and a selection of dairy products. The iodine concentration of eighty-five samples of milk and dairy products was analysed by inductively coupled plasma-MS. Low-fat milk and organic milk were sampled from nineteen and seven different locations in Norway, respectively, during the summer and winter season of 2000. Other milk and dairy products were chiefly collected during the summer season. Low-fat milk from the summer season had significantly lower median iodine concentration (88 microg/l, range 63-122 microg/l) compared with low-fat milk from the winter season (232 microg/l, range 103-272 microg/l). The median iodine concentration of organic summer milk (60 microg/l) was significantly lower than the iodine concentration of organic winter milk (127 microg/l). There were no significant differences in the low-fat-milk samples with regard to geographical sampling location. Whey cheese (Tine Gudbrandsdalsost) iodine concentration was significantly higher (803 microg/kg) than the median iodine concentration in casein cheeses such as Jarlsberg and Norvegia of 201 and 414 microg/kg, respectively. With a recommended iodine intake of 150 microg/d for adults, a daily intake of 0.4 litres milk meets the requirement with 25 % during the summer and more than 60 % during the winter season. Thus, milk and dairy products are important determinants of iodine intake in Norway.     

Changes in iodine metabolism during late pregnancy and lactation: a longitudinal study among Sudanese women

OBJECTIVE: To elucidate the persistence, or otherwise, of the pregnancy-related changes in the iodine metabolism and thyroid function in a population residing in an area of mild iodine deficiency in the Sudan. DESIGN: A longitudinal prospective cohort study involving pregnant women who were recruited during their third trimester of pregnancy and were followed up for up to nine months after delivery. SETTING: The study was conducted among Sudanese women residing in the Omdurman area in Khartoum, an area with a total goitre rate of 17.5%. Subjects: Forty-seven pregnant women were recruited during their third trimester of pregnancy. Their mean age and weight were 29+/-4.6 y and 62.4+/-8.7 kg, respectively. Age matched healthy non-pregnant women living in the same area (n=40) served as a control group. METHODS: Serum levels of thyrotropin (TSH), thyroxine (T4), triiodothyronine (T3), thyroglobulin (Tg) and the urinary iodine concentration (UIC) were determined during the third trimester (first occasion), and subsequently at three months (second occasion), six months (third occasion) and nine months after delivery (fourth occasion). Control subjects provided corresponding samples on one occasion. Main outcomes measures: UIC, TSH, Tg, FT4 and T3. RESULTS: During the third trimester of pregnancy the median UIC and the free T4 (FT4) were lower than in the control group (P<0. 0001, P<0.0001, respectively), while the median Tg was higher than in the controls (P<0.03). Three months post-partum maximum thyroidal stimulation was evident, with elevated serum levels of TSH and Tg (P<0.0001, P<0.03) and reduced UIC and serum T3 and FT4 (P<0.0004, P<0.0005, P<0.0001), compared with the control group. Nine months post-partum the thyroid function was restored to the pre-pregnancy state, and the median values of TSH, Tg, T3, FT4 and UIC did not differ significantly from those in the control group. CONCLUSIONS: Our study suggests that the reversibility of the pregnancy-induced changes in the iodine status and thyroid function to the pre-pregnancy levels may depend on the iodine status of the mother during and after pregnancy. The thyroidal stress during the first three months of the post-partum period, which is partially due to the iodine loss in the breast milk, justifies further detailed studies to assess the iodine content of the breast milk and the role of breast milk as a vehicle for iodine supply of infants in situations of iodine deficiency. SPONSORSHIP: This study was supported by a grant from the Swedish Agency for Research Co-operation with Developing Countries.     

Monitoring iodine following consumption of iodized salt in Tehrani inhabitants

As the production, distribution and consumption of iodized salt has increased in recent years, this study was carried out to assess iodine status in Tehran in 1996. 1146 families comprising 5140 subjects in the twenty districts of Tehran city from all age groups were randomly selected. Thyroid size was examined by palpation and graded according to the WHO classification. In 163 families selected randomly, thyroid size was determined by ultrasonography and urinary iodine was measured by digestion method. Serum T4, T3 and TSH (IRMA) concentrations were also assayed by kits. Percentage of grades 1 & 2 goiter were 44 & 44% in females and 49 & 33% in males respectively. Median urinary iodine was 17.5 micrograms/dl. Mean serum T4, T3 and TSH were 8.41 +/- 1.4 micrograms/dl, 170 +/- 37 ng/dl and 1.4 +/- 0.8 mu/ml, respectively. In 118 children aged 6-10 years median urinary iodine was 17.5 micrograms/dl. Thyroid volume in children was 4.3 +/- 1.9 ml. No correlation was established between the thyroid volume and goiter grade. This study points to the adequacy of iodine intake in the majority of families residing in Tehran.     

Temporal patterns in perchlorate, thiocyanate, and iodide excretion in human milk

BACKGROUND: Perchlorate and thiocyanate interfere with iodide uptake at the sodium-iodide symporter and are potential disruptors of thyroid hormone synthesis. Perchlorate is a common contaminant of water, food, and human milk. Although it is known that iodide undergoes significant diurnal variations in serum and urinary excretion, less is known about diurnal variations of milk iodide levels. OBJECTIVES: Variability in perchlorate and thiocyanate excretion in human milk has not been examined. Our objective was to determine variability of perchlorate, thiocyanate, and iodide in serially collected samples of human milk. METHODS: Ten lactating women were asked to collect six milk samples on each of 3 days. As an alternative, subjects were asked to collect as many milk samples as comfortably possible over 3 days. Samples were analyzed for perchlorate, iodide, and thiocyanate by ion chromatography coupled with mass spectrometry. RESULTS: Individual perchlorate, iodide, and thiocyanate levels varied significantly over time; there was also considerable variation among individuals. The iodide range, mean +/- SD, and median for all samples (n = 108) were 3.1-334 microg/L, 87.9 +/- 80.9 microg/L, and 55.2 microg/L, respectively. The range, mean +/- SD, and median of perchlorate in all samples (n = 147) were 0.5-39.5 microg/L, 5.8 +/- 6.2 microg/L, and 4.0 microg/L. The range, mean +/- SD, and median of thiocyanate in all samples (n = 117) were 0.4 -228.3 microg/L, 35.6 +/- 57.9 microg/L, and 5.6 microg/L. The data are not symmetrically distributed; the mean is higher than the median in all cases. CONCLUSIONS: Iodine intake may be inadequate in a significant fraction of this study population. Perchlorate and thiocyanate appear to be common in human milk. The role of these chemicals in reducing breast milk iodide is in need of further investigation.     

Iodine status remains critical in mother and infant in Central Anatolia (Kayseri) of Turkey

Summary. Background: Severe iodine deficiency disorders have been eradicated in many parts of the world, but milder forms still exist and may escape detection. Turkey has long been known to be a mild to moderate iodine deficiency area. Aim of the study: The aim of this study was to assess the iodine nutritional status and the thyroid function of pregnant women and their neonates in the region of Kayseri (central Anatolia of Turkey) that appeared to be iodine deficient in previous studies performed before the introduction of mandatory salt iodization. Methods: A cross-sectional voluntary screening study was performed in the Maternity Unit of a university hospital. A total of 70 mothers and their healthy full-term neonates were included in this study. Urinary iodine concentration was estimated in spot urine samples obtained from mothers and their neonates on day 5. All the neonates were breastfed. The iodine content was determined in the breast milk of all mothers on day 5. Serum concentrations of TSH, thyroglobulin (Tg), free triiodothyronine (FT3) and free thyroxine (FT4) were investigated in the cord serum of neonates and compared to those of mothers immediately after parturition Results: The median urinary iodine on day 5 in mothers and their babies were 30.20 and 23.80 µg/l, respectively. These figures are much lower than normal for these age groups (150–200 µg/l). The median iodine content of breast-milk was 73 µg/l. It is again much lower than in iodine sufficient areas, indicating that the status of iodine nutrition of pregnant and lactating women is clearly insufficient. The median concentrations (and ranges) of neonatal TSH, Tg, FT3 and FT4 were 7.44 mU/l, 71.62 ng/ml, 1.30 pg/ml and 1.34 ng/dl respectively. The corresponding levels for the mothers during labor were 2.19 mU/l, 25.65 ng/ml, 1.31 pg/ml and 1.23 ng/dl respectively. The median neonatal serum concentrations of TSH and Tg were significantly higher than the corresponding maternal levels (P < 0.0001, P < 0.0001, respectively) and 27.1% of the neonates had serum TSH concentrations above 10 mU/l and 57.1 % had cord blood serum Tg concentrations above 54 ng/ml. None of the mothers showed TSH concentrations above 5 mU/l and 41.4% had serum Tg concentrations above 30 ng/ml. Conclusion: Iodine deficiency with low urinary iodine excretion and high serum Tg and TSH concentrations were recognized among pregnant women and their babies in Kayseri in spite of the program of salt iodization. National measures are urgently required for improving the correction of iodine deficiency in Turkey. This includes regular supplementation with iodine, starting at preconception or in early pregnancy and continuing during the period of nursing in this region.     

某地区妊娠早期妇女碘营养状况与甲状腺功能减退症的相关性分析

目的研究分析甘肃地区妊娠早期妇女碘营养的实际情况,探究妊娠早期妇女碘营养的情况与其甲状腺功能减退症之间存在的关系。方法选取2015年2月至2016年5月于甘肃省平凉市庄浪县计划生育服务站进行常规产前检查的早期妊娠妇女200例作为研究对象,采用分光光度法测定其在空腹状态下尿碘水平以及血清中的促甲状腺激素、血清游离甲状腺素水平。结果选取的200例中早期妊娠妇女中尿碘水平的范围为8.2~1 857.8mg/L,中位数为178.3mg/L,碘缺乏总例数为79例,所占比例为39.5%,尿碘异常患者总例数为121例,所占比例为60.5%;早期妊娠妇女不同碘水平状态下血清中的促甲状腺激素有明显差异(P0.05),但血清游离甲状腺素水平无显著差异(P0.05);碘摄入异常患者的甲状腺功能减退症发生率为7.1%(9/126),显著高于碘摄入正常者的1.4%(1/74),具有统计学差异(χ~2=3.661,P0.05)。结论甘肃省平凉市庄浪县地区妊娠早期妇女中碘摄取量普遍不足,存在着碘缺乏的现象,碘摄取量不同会明显影响促甲状腺激素水平,且可能是导致甲状腺功能减退症的重要影响因素。     

碘适量地区城市妊娠妇女亚临床甲状腺功能异常的研究

目的研究碘适量地区城市妊娠妇女亚临床甲状腺功能异常状况,为今后实施妊娠妇女甲状腺功能筛查提供依据。方法随机采集杭州市5个调查点160名妊娠妇女及51名正常非妊娠妇女的血、尿样品,酸消化砷-铈接触法测定尿碘,化学发光法测定促甲状腺激素(TSH)、游离甲状腺素(FT4)、游离三碘甲状腺原氨酸(FT3)、总甲状腺素(TT4)、总三碘甲状腺原氨酸(TT3)和甲状腺过氧化物酶抗体(TPOAb)。结果妊娠早、中、晚期妇女与非妊娠妇女间尿碘水平差异均无统计学意义(Z=2.21,P=0.53);采用正常妊娠妇女甲状腺激素参考值范围检出亚临床甲状腺功能异常率为10.0%(16/160),如采用非妊娠妇女甲状腺激素正常参考值范围,妊娠妇女亚临床甲状腺功能异常漏诊率为8.75%(14/160),两种参考范围在判断亚临床甲状腺功能方面差异有统计学意义(χ2=8.46,P=0.04)。结论必须用正常妊娠妇女不同孕期甲状腺激素参考值范围对妊娠妇女甲状腺功能进行判断。虽然杭州市城市妊娠妇女人群尿碘处于适宜水平,但亚临床甲状腺功能异常检出率为10.0%,建议在早、中期妊娠妇女中开展甲状腺功能筛查。     

Urinary perchlorate and thyroid hormone levels in adolescent and adult men and women living in the United States

BACKGROUND: Perchlorate is commonly found in the environment and known to inhibit thyroid function at high doses. Assessing the potential effect of low-level exposure to perchlorate on thyroid function is an area of ongoing research. OBJECTIVES: We evaluated the potential relationship between urinary levels of perchlorate and serum levels of thyroid stimulating hormone (TSH) and total thyroxine (T4) in 2,299 men and women, > or = 12 years of age, participating in the National Health and Nutrition Examination Survey (NHANES) during 2001-2002. METHODS: We used multiple regression models of T4 and TSH that included perchlorate and covariates known to be or likely to be associated with T4 or TSH levels: age, race/ethnicity, body mass index, estrogen use, menopausal status, pregnancy status, premenarche status, serum C-reactive protein, serum albumin, serum cotinine, hours of fasting, urinary thiocyanate, urinary nitrate, and selected medication groups. RESULTS: Perchlorate was not a significant predictor of T4 or TSH levels in men. For women overall, perchlorate was a significant predictor of both T4 and TSH. For women with urinary iodine < 100 microg/L, perchlorate was a significant negative predictor of T4 (p < 0.0001) and a positive predictor of TSH (p = 0.001). For women with urinary iodine > or = 100 microg/L, perchlorate was a significant positive predictor of TSH (p = 0.025) but not T4 (p = 0.550). CONCLUSIONS: These associations of perchlorate with T4 and TSH are coherent in direction and independent of other variables known to affect thyroid function, but are present at perchlorate exposure levels that were unanticipated based on previous studies.     

Studies on the effects of rapeseed meal on thyroid status of cattle, glucosinolate and iodine content of milk and other parameters.

The effects of feeding rapeseed meals (RSM) containing low (Tower) or high (Target/Turret) levels of glucosinolates on thyroid status, iodine and glucosinolate content of milk and other parameters were studied in dairy cows and young calves. RSM (Tower and Turret) fed to dairy cows at 25% of the grain mixture reduced iodine content of milk. Diets containing Tower and Turret RSM tended to reduce plasma thyroxine (T4) in cows and increase the size of thyroids in rats. Calf diets containing Target and Tower RSM resulted in increased liver and thyroid weights, but only those containing Target tended to reduce plasma T4 levels. Feed intake, weight gain, hemoglobin, blood cell volume and erythrocyte count in calves were not affected by diets containing Tower RSM, but Target RSM reduced all these parameters. In addition, diets containing Target caused more pronounced histological changes of the calves' thyroid than those containing Tower RSM. No measurable amounts of intact glucosinolates were detected in milk of cows fed RSM. Similarly the glucosinolate aglucones, isothiocyanates or vinyl oxazolidinethione, were not transferred to milk although small amounts of unsaturated nitrile (1-cyano-2-hydroxy-3-butene) and inorganic thiocyanate were detected in milk. Rats receiving milk from cows fed Turret RSM developed larger thyroid than those receiving milk from control-fed cows. Supplemental iodine (61.0 microgram/d) in the rat prevented the thyroid enlargement.     

城乡居民碘营养及甲状腺疾病患病情况调查

目的了解杭州市城乡居民碘营养现况及甲状腺疾病患病情况。方法分别从杭州市城区和农村随机抽取3个调查点,每个调查点随机抽取100户居民,检测其家中食盐盐碘浓度,计算每日盐摄入量;采集尿样及血样,检测尿碘、血清游离三碘甲状腺原氨酸（FT3）、血清游离甲状腺素（FT4）和血清促甲状腺激素（TSH）。结果城区盐碘和每日盐摄入量中位数分别为29．40mg／kg和6．35g／d,农村盐碘和每日盐摄入量中位数分别为29．65mg／kg和8．50g／d;城区尿碘中位数为120．00μg／L,低于农村的188．73μg／L;城区临床甲减、亚临床甲减、临床甲亢、亚临床甲亢和甲状腺疾病总患病率分别为0．13％、10．13％、0．26％、0．52％和11．04％,农村临床甲减、亚临床甲减、临床甲亢、亚临床甲亢和甲状腺疾病总患病率分别为0．85％、3．12％、0．57％、1．99％和6．52％,城区亚临床甲减、甲状腺疾病总患病率高于农村,亚临床甲亢患病率则低于农村。结论杭州市城乡居民碘营养均处于适宜水平,城区居民尿碘水平低于农村,但亚临床甲减和甲状腺疾病总患病率高于农村。     

硒对高碘大鼠TGAb、TMAb、FT_3、FT_4和TSH影响的观察

目的探讨硒对高碘摄入大鼠甲状腺TGAb、TMAb、FT3、FT4和TSH的影响。方法 Wistar大鼠随机分为对照组、高碘组和高碘加硒组,高碘加硒组灌胃给予亚硒酸钠,观察各组血清TGAb、TMAb、FT3、FT4和TSH水平变化。结果各组实验前后血清FT3、FT4和TSH水平差异无显著性(P>0.05),高碘组两种抗体水平逐渐缓慢升高,自身前后对比差异有显著性(P<0.05),而高碘加硒组抗体水平变化不大(P>0.05)。结论高碘组大鼠血清自身抗体水平随着时间的延长逐步升高,而硒对此有拮抗作用。