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BACKGROUND: Although iodine modulates bone metabolism in the treatment of thyroid disease, the effect of iodine intake on bone metabolism remains less known. OBJECTIVE: This study evaluated the effect of excess iodine intake in rats on bone reconstruction in the 6th and 12th month of intervention. METHOD: Rats were treated with different doses of iodinated water: the normal group (NI, 6.15 µg/d), 5-fold high iodine group (5HI, 30.75 µg/d), 10-fold high iodine group (10HI, 61.5 µg/d), 50-fold high iodine group (50HI, 307.5 µg/d), and 100-fold high iodine group (100HI, 615 µg/d). Thyroid hormone concentrations were determined by a chemiluminescent immunoassay. Morphometry and microstructure of bone trabecula were observed by hematoxylin and eosin staining and microcomputed tomography, respectively. Alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) staining were performed to evaluate the activity of osteoblasts and osteoclasts, respectively. RESULTS: The 24-h urine iodine concentration increased with iodine intake. The rats in the HI groups had higher serum thyroid-stimulating hormone and decreased serum free thyroxine concentrations in the 12th month than the NI group (all P < 0.05). The percentage of the trabecular bone area and osteoblast perimeter in the 100HI group were significantly lower than those in the NI group (P < 0.05). Increased structure model index was observed in the 50HI and 100HI groups compared with the NI group in the 6th month and increased trabecular separation in the 12th month (all P < 0.05). ALP and TRAP staining revealed osteoblastic bone formation was reduced, and the number of TRAP+ multinucleated cells decreased with increasing iodine intake. CONCLUSIONS: Excess iodine intake may increase the risk of hypothyroidism in rats. Chronic excess iodine intake can lead to abnormal changes in skeletal structure, resulting in reduced activity of osteoblasts and osteoclasts, which inhibits the process of bone reconstruction and may lead to osteoporosis.
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Hipotireoidismo , Iodo , Osteoporose , Ratos , Animais , Tiroxina , Microtomografia por Raio-X , Hipotireoidismo/metabolismo , Osteoporose/prevenção & controle , Fosfatase AlcalinaRESUMO
This study aimed to explore the influence of excess iodine on the articular cartilage and epiphyseal growth plate in rats. Wistar rats (n = 200) were randomly divided into five groups with 40 rats in each: normal iodine (NI), 5-fold high iodine group (5HI), 10-fold high iodine group (10HI), 50-fold high iodine group (50HI), and 100-fold high iodine group (100HI). The rats were executed in 6 and 12 months. 24-h urinary iodine concentration (UIC) was monitored by arsenic-cerium catalytic spectrophotometry. The chemiluminescence method was used to determine the thyroid function. The pathological changes in the epiphyseal plate, articular cartilage, and thickness of the epiphyseal plate were observed. The mRNA expression of collagen II (ColII), collagen X, matrix metalloproteinase-13 (MMP-13), and fibroblast growth factor receptor 1 in articular chondrocytes was detected by RT-PCR. 24-h UIC increased as iodine intake increased. In the 12th month, there was a significant increase in serum sTSH and a decrease in serum FT4 in HI groups, compared to the NI group. There was a decrease in the number of proliferating cells in the epiphyseal plate and an increase in the number of mast cell layers. The chondrocytes appeared disorganized, and the tidal lines were disturbed or even broken. Growth plate thickness decreased with increasing iodine intake. Compared with the NI group, ColII and MMP-13 mRNA expression in chondrocytes in all HI groups significantly increased. Chronic iodine overdose increases the risk of hypothyroidism. Chronic iodine overdose leads to abnormal morphology of epiphyseal growth plates and articular cartilage, increasing the risk of osteoarthritis.
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BACKGROUND: Adequate breast milk iodine concentration (BMIC) is essential for the growth and cognitive development of exclusively breastfed infants; however, data on variations in BMIC over 24 h are limited. OBJECTIVE: We aimed to explore in lactating women the variation in 24-h BMIC. METHODS: Thirty pairs of mothers and breastfed infants aged 0-6 mo were recruited from the cities of Tianjin and Luoyang, China. A 3-d 24-h dietary record, including salt intake, was performed to assess the dietary iodine intake of lactating women. Breast milk samples before and after each feeding for 24 h and 24-h urine samples were collected from the women for 3 d to estimate iodine excretion. A multivariate linear regression model was used to analyze the factors influencing BMIC. A total of 2658 breast milk samples and 90 24-h urine samples were collected. RESULTS: The median BMIC and 24-h urine iodine concentration (UIC) of lactating women for a mean of 3.6 ± 1.48 mo were 158 µg/L and 137 µg/L, respectively. The interindividual variability of BMIC (35.1%) was higher than that observed within individuals (11.8%). The variation in BMIC showed a "V" shaped curve over 24 h. The median BMIC at 08:00-12:00 (137 µg/L) was significantly lower than that at 20:00-24:00 (163 µg/L) and 00:00-04:00 (164 µg/L). A progressively increasing curve was obtained for BMIC until it peaked at 20:00 and plateaued at a higher concentration from 20:00 to 04:00 than at 08:00-12:00 (all P < 0.05). BMIC was associated with dietary iodine intake (ß: 0.366; 95% CI: 0.004, 0.018) and infant age (ß: -0.432; 95% CI: -1.07, -0.322). CONCLUSIONS: Our study shows that the BMIC presents a "V" shaped curve over 24 h. We recommend that breast milk samples be collected between 08:00 and 12:00 for evaluation of the iodine status of lactating women.
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Iodo , Leite Humano , Lactente , Humanos , Feminino , Leite Humano/química , Lactação , Iodo/urina , Aleitamento Materno , China , Estado NutricionalRESUMO
OBJECTIVE: Data on iodine loss in breast milk, which are critical for establishing the appropriate dietary iodine intake for lactating women, is currently limited. A study was conducted to assess iodine loss in breast milk among Chinese lactating women to estimate the appropriate dietary intake of iodine. METHODS: A total of 54 pairs of healthy, lactating women and their infants aged 0-6 months were recruited from Tianjin and Luoyang cities in China. A 4 days infant weighing study was conducted to assess iodine loss in the breast milk of lactating women. Mothers were required to weigh and record their infants' body weights before and after each feeding for a 24 h period from 8:00 am to 8:00 am. During the weighing study, 2812 breast milk samples and 216 24-h urine samples were collected from each lactating mother for four consecutive days. In addition, a 3 days 24 h dietary record, including salt weighing and drinking water samples collecting, was performed by each lactating mother to determine dietary iodine intake during the weighing study. RESULTS: The average dietary iodine intake of lactating women was 323 ± 80 µg/d. The median breast milk iodine concentration and 24 h urinary iodine concentration of lactating women were 154 (122-181) and 135 (104-172) µg/L, respectively. The mean volume of breast milk and the mean iodine loss in the breast milk of lactating women were 711 ± 157 mL/d and 112 ± 47 µg/d, respectively. The appropriate dietary intake of iodine among lactating Chinese women is approximately 260 µg/d. CONCLUSIONS: Based on the iodine loss in breast milk (110 µg/d) found in this study, and the estimated average requirement of iodine for adults, the appropriate dietary intake of iodine among lactating Chinese women is 260 µg/d, which is higher than the 240 µg/d recommended by the China Nutrition Science Congress in 2013.
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Iodo , Leite Humano , Lactente , Adulto , Humanos , Feminino , Leite Humano/química , Lactação , Iodo/urina , Aleitamento Materno , Suplementos Nutricionais , Estado Nutricional , China , Ingestão de AlimentosRESUMO
BACKGROUND AND OBJECTIVES: Urinary iodine is an essential index of iodine nutrition evaluation. To establish the number of repeated spot urine collections necessary to reflect individual iodine status over 2 months and assess its feasibility to serve as an independent indicator of individual iodine status. METHODS AND STUDY DESIGN: We performed a longitudinal, 2-months study from May to June in 2015 of 23 apparently healthy Chinese women aged 18 to 44 (32±9) y. Spot urine samples were collected on any two days of the week, and 24-h urine samples were collected once every 6 days. RESULTS: 368 spot urine and 230 24-h urine samples were analysed. The median urinary iodine concentration (UIC) was 140.5 (75.2, 246.9) µg/L. The estimated 24-h urinary iodine excretion (24-h UIE) values from spot urine samples and measured 24-h UIE values from 24-h urine samples were 348±240 µg/24h and 330±216 µg/24h (p=0.003), respectively. Irrespective of the urinary iodine method, the intra- individual coefficient of variation (CV%) was lower than the inter-individual CV%. Bland-Altman analysis revealed differences between spot urine and 24-h urine. When the precision ranges with 95% confidence were ±15%, ±20%, ±25% or 30%, the number of an individual's spot urine samples required were 30, 16, 11 or 8, respectively. CONCLUSIONS: Repeated spot urine is not a feasible way to assess recent individual iodine intake. The development of a multi-indicator system could provide an acceptable individual evaluation index of iodine status.
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Iodo , China , Feminino , Humanos , Avaliação Nutricional , Estado Nutricional , Coleta de UrinaRESUMO
Objective: The aim of this research was to determine the correction coefficients of different spot urinary iodine concentrations (UICs) in a day to predict the early morning UIC, to make the different spot UICs of a day comparable in assessing iodine status in the same population. Methods: In total, 424 participants aged 18 to 28 years were recruited from Tianjin, China. Three spot urine samples were collected from each participant during three periods of the day (6:30-7:00, 10:00-10:30, and 16:00-16:30). A total of 1272 urine samples were collected. A 24-hour dietary record was reported by each participant for 3 consecutive days. Results: Both the UICs at 10:00-10:30 and 16:00-16:30 were higher than that at 6:30-7:00 (181.75 or 198.15µg/L vs 157.69 µg/L; all p < 0.05). Bland-Altman plot showed no good agreements between the other two spot UICs and that at 6:30-7:00 with both Bland-Altman indexes of 7.1%. Correction coefficients used to predict UIC at 6:30-7:00 from the UIC at 10:00-10:30 and 16:00-16:30 were 0.9231 and 0.8592, respectively. The predicted UICs at 6:30-7:00 by using the UIC at 10:00-10:30 and 16:00-16:30 both had no statistically significant difference with the actual UIC at 6:30-7:00 (all p > 0.05). Bland-Altman plot showed good agreements between the predicted UICs and actual UICs at 6:30-7:00 with both Bland-Altman indexes of 4.5%. Conclusions: It was reliable to predict the early morning UIC using correction coefficients of other spot UIC of the day, which gave a new idea for standardizing the methodology of surveys assessing iodine status of a population.
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Povo Asiático , Iodo/deficiência , Iodo/urina , Estado Nutricional , Adolescente , Adulto , China , Feminino , Humanos , Masculino , Adulto JovemRESUMO
There is a dearth of data on the iodine balance studies of Chinese population. In the present study, we aimed to explore the appropriate recommended nutrient intake (RNI) of iodine based on healthy Chinese women. A 4-week study was conducted in twenty-five Chinese euthyroid women. Uniform diets with different iodine contents were provided in two different periods, in which non-iodised salt was given in the first 3 weeks, followed by 1 week of iodised salt administration. The total iodine intake from diet, water and air as well as the total iodine excretion through urine, faeces and respiration were monitored and determined. The sweat iodine loss was also considered. Moreover, the regression curve model was established between the 24 h iodine intake and 24 h iodine excretion. The 24 h iodine intake in the two periods was 194·8 (sd 62·9) and 487·1 (sd 177·3) µg/d, respectively. The 24 h iodine excretion was 130·9 (sd 39·5) and 265·4 (sd 71·8) µg/d, respectively. Both 24 h iodine intake and 24 h iodine excretion of the two periods were significantly different (all P<0·05). The iodised salt contributed approximately 62·7 % of the total daily iodine intake. Moreover, 92·3 % (277/300) of samples were in positive balance, while twenty-three cases were in negative balance. Our data show that the estimated average requirement for iodine was 110·5 µg/d. Therefore, the RNI for iodine to non-pregnant, non-lactating Chinese women was 154·7 µg/d.
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Hypothyroidism due to iodine deficiency can impair physical development, most visibly in the marked stunting of myxedematous cretinism caused by severe in utero iodine deficiency. Whether iodine repletion improves growth in noncretinous children is uncertain. Therefore, the aim of our systematic review was to assess the effects of iodine fortification or supplementation on prenatal and postnatal growth outcomes in noncretinous children. Following Cochrane methods and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) reporting guidelines, we searched 10 databases including 2 Chinese databases (latest search February 2017). We included randomized and nonrandomized controlled trials (RCTs; non-RCTs), controlled before-after (CBA) studies, and interrupted time-series studies in pregnant women and children (≤18 y), which compared the effects of iodine (any form, dose, regimen) to placebo, noniodized salt, or no intervention on prenatal and postnatal growth outcomes. We calculated mean differences with 95% CIs, performed random-effects meta-analyses, and assessed the quality of evidence with the use of GRADE (Grading of Recommendations Assessment, Development and Evaluation). We included 18 studies (13 RCTs, 4 non-RCTs, 1 CBA) (n = 5729). Iodine supplementation of severely iodine-deficient pregnant women increased mean birthweight [mean difference (MD): 200 g; 95% CI: 183, 217 g; n = 635; 2 non-RCTs] compared to controls, but the quality of this evidence was assessed as very low. Iodine repletion across the other groups showed no effects on primary growth outcomes (quality of evidence mostly low and very low). Meta-analyses showed a positive effect in moderate-to-mildly iodine-deficient schoolchildren on insulin-like growth factor-1 (MD: 38.48 ng/mL; 95% CI: 6.19, 70.76 ng/mL; n = 498; 2 RCTs, low-quality evidence) and insulin-like growth factor binding protein-3 (MD: 0.46 µg/mL; 95% CI: 0.25, 0.66 µg/mL; n = 498; 2 RCTs, low-quality evidence). In conclusion, we identified few well-designed trials examining the effects of iodine repletion on growth. We are uncertain whether prenatal iodine repletion increases infant growth. Postnatal iodine repletion may improve growth factors but has no clear effects on somatic growth. Our systematic review was registered with PROSPERO as CRD42014012940.
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Deficiências Nutricionais/complicações , Suplementos Nutricionais , Retardo do Crescimento Fetal/prevenção & controle , Alimentos Fortificados , Transtornos do Crescimento/prevenção & controle , Iodo/uso terapêutico , Cloreto de Sódio na Dieta , Peso ao Nascer/efeitos dos fármacos , Feminino , Retardo do Crescimento Fetal/etiologia , Transtornos do Crescimento/etiologia , Humanos , Iodo/deficiência , Iodo/farmacologia , Fenômenos Fisiológicos da Nutrição Materna , Gravidez , Complicações na Gravidez/etiologia , Complicações na Gravidez/prevenção & controle , Cloreto de Sódio na Dieta/farmacologia , Cloreto de Sódio na Dieta/uso terapêutico , Somatomedinas/metabolismoRESUMO
Background: Dietary iodine requirements are high during pregnancy, lactation, and infancy, making women and infants vulnerable to iodine deficiency. Universal salt iodization (USI) has been remarkably successful for preventing iodine deficiency in the general population, but it is uncertain if USI provides adequate iodine intakes during the first 1000 d. Objective: We set out to assess if USI provides sufficient dietary iodine to meet the iodine requirements and achieve adequate iodine nutrition in all vulnerable population groups. Methods: We conducted an international, cross-sectional, multicenter study in 3 study sites with mandatory USI legislation. We enrolled 5860 participants from 6 population groups (school-age children, nonpregnant nonlactating women of reproductive age, pregnant women, lactating women, 0-6-mo-old infants, and 7-24-mo-old infants) and assessed iodine status [urinary iodine concentration (UIC)] and thyroid function in Linfen, China (n = 2408), Tuguegarao, the Philippines (n = 2512), and Zagreb, Croatia (n = 940). We analyzed the iodine concentration in household salt, breast milk, drinking water, and cow's milk. Results: The salt iodine concentration was low (<15 mg/kg) in 2.7%, 33.6%, and 3.1%, adequate (15-40 mg/kg) in 96.3%, 48.4%, and 96.4%, and high (>40 mg/kg) in 1.0%, 18.0%, and 0.5% of household salt samples in Linfen (n = 402), Tuguegarao (n = 1003), and Zagreb (n = 195), respectively. The median UIC showed adequate iodine nutrition in all population groups, except for excessive iodine intake in school-age children in the Philippines and borderline low intake in pregnant women in Croatia. Conclusions: Salt iodization at â¼25 mg/kg that covers a high proportion of the total amount of salt consumed supplies sufficient dietary iodine to ensure adequate iodine nutrition in all population groups, although intakes may be borderline low during pregnancy. Large variations in salt iodine concentrations increase the risk for both low and high iodine intakes. Strict monitoring of the national salt iodization program is therefore essential for optimal iodine nutrition. This trial was registered at clinicaltrials.gov as NCT02196337.
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Deficiências Nutricionais/prevenção & controle , Iodo/deficiência , Política Nutricional , Estado Nutricional , Cloreto de Sódio na Dieta/administração & dosagem , Adolescente , Adulto , Animais , Aleitamento Materno , Bovinos , Criança , Pré-Escolar , China/epidemiologia , Croácia/epidemiologia , Estudos Transversais , Deficiências Nutricionais/epidemiologia , Deficiências Nutricionais/urina , Dieta , Água Potável/química , Feminino , Humanos , Lactente , Recém-Nascido , Iodo/administração & dosagem , Iodo/urina , Lactação , Masculino , Leite/química , Leite Humano , Necessidades Nutricionais , Filipinas/epidemiologia , Gravidez , Complicações na Gravidez/prevenção & controle , Complicações na Gravidez/urina , Prevalência , Cloreto de Sódio na Dieta/urina , Adulto JovemRESUMO
OBJECTIVE: High salt intake among lactating women can increase the risk of hypertension and cardiovascular disease in infants/offspring. However, considering the limited salt intake data in lactating women, the aims of this study were to compare the salt intake assessed by modified food weighted records (FWR) with that estimated by 24-h urinary sodium excretion and to investigate the salt intake of lactating women. METHODS: In total, 30 lactating women aged 20-39 years who were 2 to 4 months postpartum were recruited from the cities of Tianjin and Luoyang in China. The household salt intakes of the lactating women were collected by modified FWR for 3 days. Information on the gender, age, eating behaviours and labour intensity of the family members and guests dining at home during the 3 days was recorded. Meanwhile, 24-h urine samples of lactating women were collected. RESULTS: The salt intakes of the lactating women estimated by modified FWR and 24-h urinary sodium excretion were 8.50 ± 5.32 g/d and 9.34±3.74 g/d (t=-1.29, P=0.207), respectively, which exceeded the WHO recommendation of 5 g/d. There was a significant correlation (r=0.628, P < 0.001) between the salt intakes assessed by the two methods. A Bland-Altman plot showed no significant mean difference between the two methods (salt intake measured by 24-h urinary sodium excretion-salt intake assessed by modified FWR=0.46 g/d, P=0.207). CONCLUSIONS: The modified FWR is a reliable tool to assess the salt intake of lactating women. The salt intake of lactating women in China remains higher than the WHO recommendation and should be restricted through further efforts.
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Lactação , Cloreto de Sódio na Dieta/administração & dosagem , Adulto , China , Registros de Dieta , Feminino , Humanos , Recomendações Nutricionais , Adulto JovemRESUMO
Background: Iodine status in populations is usually assessed by the median urinary iodine concentration (UIC). However, iodine is also excreted in breast milk during lactation; thus, breast milk iodine concentration (BMIC) may be a promising biomarker of iodine nutrition in lactating women. Whether the mammary gland can vary fractional uptake of circulating iodine in response to changes in dietary intake is unclear.Objective: We evaluated UIC and BMIC as biomarkers for iodine status in lactating women with a wide range of iodine intakes.Methods: We recruited 866 pairs of lactating mothers and exclusively breastfed infants from 3 iodine-sufficient study sites: Linfen, China (n = 386); Tuguegarao, Philippines (n = 371); and Zagreb, Croatia (n = 109). We also recruited iodine-deficient lactating women from Amizmiz, Morocco (n = 117). We collected urine and breast milk samples and measured UIC and BMIC.Results: In the 3 iodine-sufficient sites, a pooled regression analysis of the estimated iodine excretion revealed higher fractional iodine excretion in breast milk than in urine at borderline low iodine intakes. In contrast, in the iodine-deficient site in Morocco, a constant proportion (â¼33%) of total iodine was excreted into breast milk.Conclusions: In iodine-sufficient populations, when iodine intake in lactating women is low, there is increased partitioning of iodine into breast milk. For this reason, maternal UIC alone may not reflect iodine status, and BMIC should also be measured to assess iodine status in lactating women. Our data suggest a BMIC reference range (2.5th and 97.5th percentiles) of 60-465 µg/kg in exclusively breastfeeding women. This trial was registered at clinicaltrials.gov as NCT02196337.
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Aleitamento Materno , Iodo/química , Iodo/urina , Leite Humano/química , Adulto , Biomarcadores , China , Croácia , Estudos Transversais , Feminino , Humanos , Marrocos , Estado Nutricional , Filipinas , Adulto JovemRESUMO
INTRODUCTION: Iodine is an essential micronutrient and component of the thyroid hormones. Sufficient ingestion of iodine is necessary for normal growth and development. If iodine requirements are not met, growth can be impaired. Salt iodisation and supplementation with iodine can prevent iodine deficiency disorders and stunted growth. No systematic review has yet collated the evidence linking iodine to growth. With an increased emphasis on stunting within the WHO Global Nutrition Targets for 2025, we propose a systematic review to address this question. METHODS AND ANALYSIS: We will undertake a systematic review, and if appropriate, meta-analyses, evaluating the effects of iodised salt or iodine supplements on prenatal and postnatal somatic growth, until age 18. We will search a number of databases, including MEDLINE, EMBASE, Web of Science, CINAHL, PsychINFO, the Cochrane Library, including the CENTRAL register of Controlled Trials and also the WHO library and ICTRP (International Clinical Trials Registry Platform), which includes the Clinicaltrials.gov repository. We will also search Wanfang Data and the China Knowledge Resource Integrated Database. Included studies must have compared exposure to iodised salt, iodine supplements or iodised oil, to placebo, non-iodised salt or no intervention. Primary outcomes will be continuous and categorical markers of prenatal and postnatal somatic growth. Secondary outcomes will cover further measures of growth, including growth rates and indirect markers of growth such as insulin-like growth factor-1 (IGF-1). ETHICS AND DISSEMINATION: The systematic review will be published in a peer-reviewed journal, and will be sent directly to the WHO, United Nations Children's Fund, International Council for the Control of Iodine Deficiency Disorders and other stakeholders. The results generated from this systematic review will provide evidence to support future programme recommendations regarding iodine fortification or supplementation and child growth. TRIAL REGISTRATION NUMBER: PROSPERO CRD42014012940.
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Transtornos do Crescimento/dietoterapia , Hormônio do Crescimento/metabolismo , Transtornos da Nutrição do Lactente/dietoterapia , Iodo/farmacologia , Micronutrientes/administração & dosagem , Cloreto de Sódio na Dieta/farmacologia , Suplementos Nutricionais , Feminino , Transtornos do Crescimento/etiologia , Transtornos do Crescimento/prevenção & controle , Humanos , Transtornos da Nutrição do Lactente/etiologia , Transtornos da Nutrição do Lactente/prevenção & controle , Fenômenos Fisiológicos da Nutrição do Lactente , Recém-Nascido , Iodo/administração & dosagem , Iodo/deficiência , Micronutrientes/deficiência , Sistema Hipófise-Suprarrenal/fisiopatologia , Gravidez , Cloreto de Sódio na Dieta/administração & dosagem , Revisões Sistemáticas como AssuntoRESUMO
OBJECTIVE: The effects of long-term excessive maternal iodine intake on neonatal thyroid function are less known. This study aimed to assess the effects of maternal excessive iodine intake from drinking water on thyroid functions of both mothers and their neonates. DESIGN AND METHODS: This observational study was performed in high iodine (HI) areas and adequate iodine (AI) intake areas, including 384 healthy pregnant women in late gestation (mean week 39·3 ± 1·6 weeks) and their newborns. Blood and urine samples were obtained from pregnant women, while cord blood samples were obtained from neonates. Urinary iodine concentration (UIC) and thyroid function were evaluated. RESULTS: The median maternal UIC was 1241 and 217 µg/l in HI and AI areas, respectively (P < 0·001). The concentrations of serum thyroid-stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) in neonates in HI areas were 7·33 mIU/l (range 5·47, 11·06 mIU/l), 2·93 ± 0·59 and 15·03 ± 1·92 pmol/l, respectively, while that were 4·71 mIU/l (range 3·96, 6·04 mIU/l), 2·31 ± 0·28 and 16·50 ± 1·35 pmol/l in AI neonates (P < 0·05). Similar changes were also observed in neonates in HI areas when excluding the effect of maternal thyroid autoimmunity. Cord blood TSH concentration (r = 0·31, P = 0·001) and FT3 concentration (r = 0·43, P = 0·001) were positively correlated with maternal UIC. Cord blood FT4 concentration was negatively correlated with maternal UIC (r = -0·25, P = 0·001). Mothers living in HI areas (ß = 0·296, 95% CI: 0·163, 0·255) and with subclinical hypothyroidism (ß = 0·360, 95% CI: 0·034, 0·175) contributed to elevated cord blood TSH concentration in neonates, while male neonates were more likely to present with higher TSH concentration compared with female infants (ß = -0·760, 95% CI: -0·119, -0·033). CONCLUSIONS: Excessive iodine intake during pregnancy was associated with an increased rate of hyperthyrotropinaemia in neonates and their mothers, especially in male neonates.
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Água Potável/química , Iodo/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Glândula Tireoide/efeitos dos fármacos , Adulto , China , Estudos Transversais , Feminino , Sangue Fetal/química , Geografia , Humanos , Recém-Nascido , Iodo/administração & dosagem , Iodo/urina , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/sangue , Efeitos Tardios da Exposição Pré-Natal/urina , Testes de Função Tireóidea , Glândula Tireoide/fisiopatologia , Tireotropina/sangue , Tiroxina/sangue , Tri-Iodotironina/sangue , Adulto JovemRESUMO
OBJECTIVE: To explore (i) the prevalence of thyroid dysfunction in populations with adequate and excessive iodine intakes and (ii) the effect of iodine exposure on the prevalence of thyroid dysfunction. DESIGN: Cross-sectional study was conducted in Hebei in 2010. The population was classified as having adequate or excessive iodine intake according to the iodine concentration in drinking water. Demographic information was collected by questionnaire. Levels of serum thyroid hormones, thyroid autoantibodies and iodine in drinking water and urine were measured. SETTING: Villages with adequate or excessive drinking water iodine in Hebei Province, People's Republic of China. SUBJECTS: A total of 854 men and women aged 20-50 years who had lived in the surveyed areas for over 5 years, including 348 from the adequate iodine area (AIA) and 506 from the excessive iodine area (EIA). RESULTS: Median urinary iodine concentration was 185 µg/l in AIA and 1152 µg/l in EIA. The prevalence of thyroid dysfunction in AIA was 10.3%, which included 1.1% with hypothyroidism and 8.1% with subclinical hypothyroidism; and 20.6% in EIA, which included 3.6% with hypothyroidism and 13.6% with subclinical hypothyroidism. The positive rates of thyroglobulin antibody were 16.1% in AIA and 11.9% in EIA; the positive rates of thyroperoxidase antibody were 20.7% in AIA and 16.4% in EIA. CONCLUSIONS: Excessive iodine intake may lead to increased prevalence of biochemical thyroid dysfunction, especially biochemical hypothyroidism. This is not related to an increase in prevalence of thyroid antibodies. Women are more susceptible to iodine excess.
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Iodo/administração & dosagem , Iodo/efeitos adversos , Doenças da Glândula Tireoide/epidemiologia , Adulto , China/epidemiologia , Estudos Transversais , Água Potável/análise , Feminino , Humanos , Iodeto Peroxidase/análise , Iodo/urina , Masculino , Pessoa de Meia-Idade , Prevalência , Inquéritos e Questionários , Tireoglobulina/análise , UrináliseRESUMO
OBJECTIVE: Long time exhaled oxygen will induced oxygen toxicity. Some studies had found that different pathology may exised in normobaric and hyperbaric pulmonary oxygen toxicity, and nitric oxide synthase (NOS) may play a role. In this study, we discussed the change of NOS in normobaric and hyperbaric pulmonary oxygen toxicity. METHODS: Sixty male SD rats were randomly divided into 6 groups (n = 10), exposed to 1 ATA (atmosphere absolute), 1.5 ATA, 2 ATA, 2.5 ATA and 3 ATA, 100% oxygen for 56, 20, 10, 8, 6 hours respectively. Rats were exposed to air as control. After exposure, the protein in bronchoalveolar lavage fluid (BALF), the wet/dry weight of lung and the expression of eNOS, nNOS in lung were defined. RESULTS: As compared to air group, the protein in BALF, the wet/dry of lung were significantly elevated in 1.0 ATA group, while these changes were not so obviously in the other groups, and these changes in hyperbaric oxygen group (approximately 1.0 ATA) were significantly decreased as compared with nonnrmobaric oxygen group (1.0 ATA). The expression of nNOS were not changed in normobaric and hyperbaric pulmonary oxygen toxicity, while the expression of eNOS was significantly decreased in 2 ATA group, and significantly elevated in 2.5 ATA and 3 ATA group. CONCLUSION: The expression of eNOS can change when exposed to different pressures of oxygen.
Assuntos
Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico Sintase Tipo I/metabolismo , Oxigênio/intoxicação , Pressão , Animais , Modelos Animais de Doenças , Pulmão/metabolismo , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Previous studies have indicated an association between iodine excess and increased incidence of thyroid dysfunction in adults. However, there have been few studies on how the intake of excessive iodine affects thyroid function in children. The objective of this study was to assess the effects of a long-term exposure to excessive iodine on thyroid dysfunction in children. Urinary iodine concentration (UIC) and thyroid function in 371 children from a high iodine (HI) area (water iodine: 150-963 µg/L) and 150 children from an adequate iodine (AI) area (water iodine: 12.8-50.9 µg/L) were measured. The water iodine concentration in the HI area was higher than that in the AI area (P < 0.001) and the median urinary iodine concentration of children in the HI area was 1030 µg/L, which was 8.6 times that of children in the AI area (123 µg/L) (P < 0.001). Children in the HI area had a higher concentration of sensitive thyroid stimulating hormone and higher positivity of both thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb). The prevalence of thyroid diseases was higher in HI area children than that in AI area children (P = 0.000), especially subclinical hypothyroidism (SCH; P = 0.004). A body mass index (BMI) of ≥ 22.3 kg/m(2) was associated with the incidence of SCH (OR: 5.51; 95% CI: 1.52, 19.9; P = 0.009). UIC ≥ 600 µg/L (OR: 3.62; 95% CI: 1.22, 10.8; P = 0.024) and TPOAb or TGAb-positivity (Ab+ OR: 6.48; 95% CI: 1.78, 23.6; P = 0.005) in children were significantly and independently associated with SCH. Interactions between UIC ≥ 800 µg/L and Ab+ (P-interaction = 0.004) were found. Furthermore, increased thyroid volume was correlated with higher UIC (ß = 0.22; P = 0.002). Excessive iodine intake in children in HI areas is associated with impaired thyroid function; UIC ≥ 600 µg/L and Ab+ are the risk factors for SCH. Effective measures need to be taken for reducing excessive iodine intake.
Assuntos
Iodo/administração & dosagem , Glândula Tireoide/fisiopatologia , Água/química , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Testes de Função TireóideaRESUMO
OBJECTIVE: To investigate the iodine nutrition status of the susceptible population after stop supplying iodized salt and discuss whether there is iodine nutritional status difference in different populations in high-iodine areas in China. METHODS: Spot investigation methods were being used, 371 children, 506 adults and 210 cases of pregnant women during the third trimester were selected as respondents. The morning Urine was collected to determinate the urine iodine level. Drinking water was collected to determinate the local water iodine level. RESULTS: The water iodine level was between 150.3-962.6 microg/L in investigation areas; The median urinary iodine (MUI) of children, adults and pregnant woman was respective 1032.08 microg/L, 1152.01 microg/L and 1240.70 microg/L. Meanwhile 96.2% children and 93.1% adults urine iodine level was more than 300 microg/L and 84.3% of pregnant women urine iodine level was more than 500 microg/L, which belongs to excessive iodine intake. The chi-square test on the distribution of urinary iodine indicate that there is statistical differences in three different population (chi2 = 44.84, P = 0.000). Kruskal-Wallis H test show that the MUI in three different crowd are not all the same (chi2 = 12.83, P = 0.002), when compared by pairs, the difference in MUI between pregnant and children or adults was founded. CONCLUSION: The iodine nutrition status of children, adult and the third trimester pregnant women in high water regions were iodine excess. The monitor on iodine nutrition status in different peoples should be enhanced. Urinary iodine level of Children can't completely represent the iodine nutritional status of pregnant women, iodine nutritional status monitor standard for pregnant women should be established.
Assuntos
Iodo/análise , Iodo/urina , Estado Nutricional , Abastecimento de Água/análise , Adolescente , Adulto , Criança , China , Feminino , Humanos , Iodo/administração & dosagem , Masculino , Pessoa de Meia-Idade , Gravidez , Terceiro Trimestre da Gravidez , População Rural , Cloreto de Sódio na Dieta , Adulto JovemRESUMO
OBJECTIVE: To investigate the iodine status and the prevalence of thyroid disease and dyslipidemia in adults living in areas of excessive iodine in water in Hebei Province, and to explore the impact of excessive iodine intake on dyslipidemia. METHODS: Subjects were selected from Haixing County in Cangzhou, Hebei. Fasting morning urine and venous blood were collected to test the levels of urinary iodine and serum free triiodothyronine (FT3), free thyroxine (FT4), and sensitive thyroid-stimulating hormone (sTSH). Thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TGAb) and total cholesterol (CHO), triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) were also measured. RESULTS: The median of urinary iodine was 1094.92 (627.38 - 1511.81) microg/L. There were 66 (22.0%) adults diagnosed as thyroid disorder, including 3 (1.0%) hyperthyroidism patients, 7 (2.3%) subclinical hyperthyroidism patients, 12 (4.0%) hypothyroidism patients and 44 (14.7%) subclinical hypothyroidism patients. The levels of CHO, TG, HDL-C and LDL-C were (5.46 +/- 1.06) mmol/L, 2.19 (1.70 - 2.96) mmol/L, 1.18 (1.03 - 1.45) mmol/L and (3.08 +/- 1.05) mmol/L respectively, no significant difference was observed between the thyroid disorder patients or non-patients. CONCLUSION: The prevalence of dyslipidemia in adults living in areas of excessive iodine in water was high.
Assuntos
Dislipidemias/epidemiologia , Iodo/análise , Adulto , Autoanticorpos , China/epidemiologia , Humanos , Hipotireoidismo , Iodetos , Iodo/metabolismo , Lipídeos/sangue , Prevalência , Doenças da Glândula Tireoide , Testes de Função Tireóidea , Tireotropina , Tiroxina , Tri-Iodotironina , Abastecimento de ÁguaRESUMO
OBJECTIVE: To reveal the iodine status of pregnant women and its impact on thyroid function of neonates in high iodine area. METHODS: A total of 210 pregnant women were chosen from a hospital in Haixing county, Hebei province. Pregnant women's random urinary and neonates' cord blood were collected. The urinary iodine concentration (UIC) was examined by arsenic-cerium catalytic spectrophotometry. The levels of free triiodothyronine (FT3), free thyroxine (FT4) and sensitive thyroid-stimulating hormone (sTSH) in serum were measured by chemiluminescence. RESULTS: The age of 210 pregnant women was (27.69 +/- 4.73) years old, whose urinary iodine median (inter-quartile range ) was 1240.70 (1292.68) microg/L. 84.3% (177/210) of the pregnant women had excessive iodine intake (UIC > or = 500 microg/L), 13.8% (29/210) had more than adequate iodine intake( UIC within 250 - 499 microg/L), 0.5% (1/210) had adequate iodine intake (UIC within 150 - 249 microg/L) and 1.4% (3/210) had insufficient iodine intake (UIC < 150 microg/L). The average serum level of FT3, FT4 in neonates were (2.93 +/- 0.59), (15.03 +/- 1.92) pmol/L, respectively. The median (inter-quartile range) of serum sTSH in neonates were 7.33 (5.59) mU/L 78.1% (164/210) of the neonates' serum TSH were beyond 5 mU/L. There were no correlation between pregnant women's urinary iodine level and neonates' serum FT3 and sTSH level (P > 0.05), but there was a positive correlation between pregnant women's urinary iodine level and neonates' serum FT4 level (P < 0.01). Serum FT4 level of the neonates with whose mothers had insufficient iodine intake ((12.99 +/- 1.10) pmol/L) were statistically lower than those with their mothers had excessive iodine intake (15.16 +/- 1.83) pmol/L) (P < 0.05). CONCLUSION: Most of the pregnant women in high iodine area were excessive for iodine nutrition, but still a few pregnant women had insufficient iodine nutrition. The level of neonates' serum sTSH were relatively high and monitoring of risk of hypothyroidism and subclinical hypothyroidism should be strengthened.
Assuntos
Sangue Fetal/química , Iodo/urina , Estado Nutricional , Adulto , China/epidemiologia , Feminino , Humanos , Hipotireoidismo/epidemiologia , Recém-Nascido , Gravidez , Testes de Função Tireóidea , Glândula Tireoide , Tireotropina/sangue , Tiroxina/sangue , Topografia Médica , Tri-Iodotironina/sangue , Adulto JovemRESUMO
CONTEXT: Adequate iodine intake during pregnancy is essential for both the synthesis of maternal thyroid hormones and the maintenance of normal fetal brain development. Scant evidence is available on the effects of excessive iodine intake during pregnancy. OBJECTIVE: The study assesses the relationship between iodine nutritional status and thyroid function of pregnant women with excessive iodine intake during late gestation. DESIGN AND PARTICIPANTS: A cross-sectional study of 384 pregnant women was carried out in Tianjin and Haixing from April to October in 2010. MAIN OUTCOME MEASURES: Morning urine samples and blood samples were obtained from all subjects. Serum levels of free T(3), free T(4), and sensitive TSH and urinary iodine concentration were measured. RESULTS: The median urinary iodine concentration of pregnant women with excessive iodine intake was significantly higher than those with adequate iodine intake (P < 0.001). The prevalence of thyroid disease, especially subclinical hypothyroidism, in pregnant women with excessive iodine intake was significantly higher than in those with adequate iodine intake (P < 0.05). Subclinical hypothyroidism was the most frequent pattern of thyroid disease for pregnant women and those with positive or negative thyroid autoantibodies. Living with high water iodine content and having urinary iodine concentration higher than 250 µg/liter are associated risk factors for subclinical hypothyroidism in pregnant women (OR(1) = 41.822, OR(2) = 6.202; P < 0.05, where OR(1) is the odds ratio for living with high water iodine content and hypothyroidism and OR(2) is the odds ratio for urinary iodine concentration >250 µg/liter and hypothyroidism). CONCLUSIONS: Excessive iodine intake during late pregnancy may lead to maternal thyroid dysfunction, particularly subclinical hypothyroidism. The appropriate measurements should be performed to monitor the onset of hypothyroidism in pregnant women with excessive iodine intake.