scholarly journals Variation of iodine status during pregnancy and its associations with thyroid function in women from Rio de Janeiro, Brazil

2019 ◽  
pp. 1-9 ◽  
Author(s):  
Carolina Martins Corcino ◽  
Tatiana Martins Benvenuto Louro Berbara ◽  
Débora Ayres Saraiva ◽  
Nathalie Anne de Oliveira e Silva de Morais ◽  
Annie Schtscherbyna ◽  
...  

AbstractObjectiveTo assess iodine status and its effects on maternal thyroid function throughout pregnancy.DesignIn the present prospective cohort study, three urinary samples were requested for urinary iodine concentration (UIC) determinations in both the first and third gestational trimesters. Serum thyrotropin (TSH) and free thyroxine (FT4) were analysed in both trimesters and thyroid antibodies were assessed once.SettingRio de Janeiro, Brazil.ParticipantsFirst-trimester pregnant women (n243), of whom 100 were re-evaluated during the third trimester.ResultsIodine sufficiency was found in the studied population (median UIC=216·7 µg/l). The first- and third-trimester median UIC was 221·0 and 208·0 µg/l, respectively. TSH levels (mean (sd)) were higher in the third trimester (1·08 (0·67)v. 1·67 (0·86) mIU/l;P<0·001), while FT4levels decreased significantly (1·18 (0·16)v. 0·88 (0·12) ng/dl;P<0·001), regardless the presence of iodine deficiency (UIC<150 µg/l) or circulating thyroid antibodies. UIC correlated (β; 95% CI) independently and negatively with age (–0·43; –0·71, –0·17) and positively with multiparity (0·15; 0·02, 0·28) and BMI (0·25; 0·00, 0·50). Furthermore, median UIC per pregnant woman tended to correlate positively with TSH (0·07; –0·01, 0·14). Women with median UIC≥250 µg/l and at least one sample ≥500 µg/l throughout pregnancy had a higher risk of subclinical hypothyroidism (OR=6·6; 95% CI 1·2, 37·4).ConclusionsIn this cohort with adequate iodine status during pregnancy, excessive UIC was associated with an increased risk of subclinical hypothyroidism.

2020 ◽  
Vol 124 (9) ◽  
pp. 971-978
Author(s):  
Zhengyuan Wang ◽  
Wei Jin ◽  
Zhenni Zhu ◽  
Xueying Cui ◽  
Qi Song ◽  
...  

AbstractAs city residents eat out more frequently, it is unknown that if iodised salt is still required in home cooking. We analysed the relationship of household salt and eating out on urinary iodine concentration (UIC) in pregnant women. A household condiment weighing method was implemented to collect salt data for a week. A household salt sample was collected. A urine sample was taken at the end of the week. Totally, 4640 participants were investigated. The median UIC was 139·1 μg/l in pregnant women and 148·7, 140·0 and 122·9 μg/l in the first, second and third trimesters. Median UIC in the third trimester was lower than in the other trimesters (P < 0·001). The usage rates of iodised (an iodine content ≥ 5·0 mg/kg) and qualified-iodised (an iodine content ≥ 21·0 mg/kg) salt were 73·9 and 59·3 %. The median UIC in the qualified-iodised salt group was higher than in the non-iodised group (P = 0·037). The median UIC in the non-iodised group who did not eat out was lower than in qualified-salt groups who both did and did not eat out (P = 0·007, <0·001). The proportion of qualified-iodised salt used in home cooking is low, but foods eaten out have universal salt iodisation according to the national compulsory policy. Household iodised salt did not play a decisive role in the iodine status of pregnant women. Pregnant women in their third trimester who are not eating out and using non-iodised salt at home require extra iodine.


2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 1037-1037
Author(s):  
Abu abdullah Mohammad Hanif ◽  
Md Mokbul Hossain ◽  
Mehedi Hasan ◽  
Abu Ahmed Shamim ◽  
Malay Kanti Mridha

Abstract Objectives Optimum Iodine status during pregnancy and lactation is crucial for normal fetal growth and child development. We assessed the urinary iodine concentration of pregnant and lactating women to determine their iodine status and measured salt iodine from their households. Methods We collected spot urine samples and corresponding household salt samples from 80 pregnant women (37 and 43 second and third-trimester women, respectively) and 49 lactating women (with children &lt;6 months). Urinary iodine was determined by manual digestion with ammonium persulfate followed by Sandell-Kolthoff Reaction using 96 multi-well plates and a micro-plate reader at 405 nm. The iodine content in salt was measured by iodometric titration method. Samples were analyzed at the icddr, b Immunology, Nutrition, and Toxicology Laboratory, Dhaka, Bangladesh. Results The median [IQR] UIC in the second-trimester women, third-trimester women, and lactating women was 90.6[41.9–171.5] mcg/L, 67.9[24.2–144.5] mcg/L, and 74.7[48.1–134.8] mcg/L, respectively. More than three-quarters of pregnant women (73% of the second-trimester women and 79% of the third-trimester women) and more than half of the lactating mothers (57%) were below the WHO recommended cut-offs. Only 42% of the household salts were adequately iodized. A moderate positive linear relationship was found between urinary and household salt iodine content (r = 0.51, P &lt; 0.0001). Conclusions Even with mandatory salt iodization policy in Bangladesh for about three decades, the iodine insufficiency among pregnant and lactating women is widespread and needs to be improved through ensuring the availability of adequately iodized salt or supplement. Funding Sources ETH Zurich, Switzerland.


2020 ◽  
Author(s):  
Zhengyuan Wang ◽  
Yiwen Wu ◽  
Zehuan Shi ◽  
Jun Song ◽  
Guoquan Wang ◽  
...  

Abstract Background: China’s universal salt-iodization program has all but eliminated iodine deficiency disorders. Concern has shifted to mild iodine deficiency. Our study examined factors with the potential to predict mild iodine deficiency in pregnant women. Methods: A total of 2 400 pregnant women were enrolled using a multistage, stratified, random-sampling method. Data were collected through face-to-face interviews, a standardized questionnaire, an iodine-related knowledge questionnaire, urine samples, and household cooking salt samples. Results: The median urinary iodine concentration (MUIC) was 148.0 μg/L for all participants, and 155.0 μg/L, 151.0 μg/L, and 139.6 μg/L in the first, second, and third trimesters, respectively. The third trimester’s MUIC was significantly lower than that of the first trimester, and the usage rates of iodized salt and qualified-iodized salt were 71.5% and 59.4%, respectively. Iodine-related knowledge was significantly different between the high and low UIC groups. Participants’ MUIC increased significantly with increases in iodine-related knowledge. The third trimester was a significant risk factor for high UIC, whereas abundant iodine-related knowledge, study the dietary knowledge urgently, and consumption of iodine-rich food within 48 hours of a urine iodine test were significant protective factors for high UIC (P<0.05). Conclusions: Iodine levels are adequate among pregnant women in Shanghai during the first and second trimesters, but insufficient in the third trimester. The use of iodized cooking salt does not determine the iodine status of pregnant women. Abundant iodine-related knowledge is important for pregnant women in the third trimester to maintain adequate urinary iodine.


2020 ◽  
Vol 105 (9) ◽  
pp. e3451-e3459 ◽  
Author(s):  
Wenxing Guo ◽  
Ziyun Pan ◽  
Ying Zhang ◽  
Ya Jin ◽  
Shuyao Dong ◽  
...  

Abstract Context The effectiveness of saliva iodine concentration (SIC) in evaluating iodine status in children is not clear. Objective We aimed to explore associations between SIC and assessed indicators of iodine status and thyroid function. Design Cross-sectional study. Setting Primary schools in Shandong, China. Participants Local children aged 8 to 13 years with no known thyroid disease were recruited to this study. Main outcome measures Blood, saliva, and urine samples were collected to evaluate thyroid function and iodine status. Results SIC positively correlated with spot urinary iodine concentration (r = 0.29, P &lt; 0.0001), 24-hour urinary iodine concentration (r = 0.35, P &lt; 0.0001), and 24-hour urinary iodine excretion (r = 0.40, P &lt; 0.0001). The prevalence of thyroid nodules (TN) and goiter showed an upward trend with SIC quantiles (P for trend &lt; 0.05). Children with SIC &lt;105 μg/L had a higher risk of insufficient iodine status (OR = 4.18; 95% CI, 2.67-6.56) compared with those with higher SIC. Those having SIC &gt;273 μg/L were associated with greater risks of TN (OR = 2.70; 95% CI, 1.38-5.26) and excessive iodine status (OR = 18.56; 95% CI, 5.66-60.91) than those with lower SIC values. Conclusions There is a good correlation between SIC and urinary iodine concentrations. It is of significant reference value for the diagnosis of iodine deficiency with SIC of less than 105 μg/L and for the diagnosis of iodine excess and TN with SIC of more than 273 μg/L. Given the sanitary nature and convenience of saliva iodine collection, SIC is highly recommended as a good biomarker of recent iodine status in school-aged children.


2018 ◽  
Vol 7 (5) ◽  
pp. 762-767 ◽  
Author(s):  
Verônica Carneiro Borges Mioto ◽  
Ana Carolina de Castro Nassif Gomes Monteiro ◽  
Rosalinda Yossie Asato de Camargo ◽  
Andréia Rodrigues Borel ◽  
Regina Maria Catarino ◽  
...  

Objectives Iodine deficiency during pregnancy is associated with obstetric and neonatal adverse outcomes. Serum thyroglobulin (sTg) and thyroid volume (TV) are optional tools to urinary iodine concentration (UIC) for defining iodine status. This cross-sectional study aims to evaluate the iodine status of pregnant women living in iodine-adequate area by spot UIC and correlation with sTg, TV and thyroid function. Methods Two hundred and seventy-three pregnant women were evaluated at three trimesters. All had no previous thyroid disease, no iodine supplementation and negative thyroperoxidase and thyroglobulin antibodies. Thyroid function and sTg were measured using electrochemiluminescence immunoassays. TV was determined by ultrasonography; UIC was determined using a modified Sandell–Kolthoff method. Results Median UIC was 146 µg/L, being 52% iodine deficient and only 4% excessive. TSH values were 1.50 ± 0.92, 1.50 ± 0.92 and 1.91 ± 0.96 mIU/L, respectively, in each trimester (P = 0.001). sTg did not change significantly during trimesters with median 11.2 ng/mL and only 3.3% had above 40 ng/mL. Mean TV was 9.3 ± 3.4 mL, which positively correlated with body mass index, but not with sTg. Only 4.5% presented with goitre. When pregnant women were categorized as iodine deficient (UIC < 150 µg/L), adequate (≥150 and <250 µg/L) and excessive (≥250 µg/L), sTg, thyroid hormones and TV at each trimester showed no statistical differences. Conclusions Iodine deficiency was detected frequently in pregnant women living in iodine-adequate area. sTg concentration and TV did not correlate to UIC. Our observation also demonstrated that the Brazilian salt-iodization programme prevents deficiency, but does not maintain iodine status within adequate and recommended ranges for pregnant women.


Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3483
Author(s):  
Inger Aakre ◽  
Lidunn Tveito Evensen ◽  
Marian Kjellevold ◽  
Lisbeth Dahl ◽  
Sigrun Henjum ◽  
...  

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.


2012 ◽  
Vol 109 (12) ◽  
pp. 2276-2284 ◽  
Author(s):  
Stefanie Vandevijvere ◽  
Sihame Amsalkhir ◽  
Ahmed Bensouda Mourri ◽  
Herman Van Oyen ◽  
Rodrigo Moreno-Reyes

Low iodine intake during pregnancy may cause thyroid dysfunction in pregnant women and their newborn. In the present study, iodine status among a nation-wide representative sample of Belgian pregnant women in the first and third trimester of pregnancy was determined, and determinants of iodine status were assessed 1 year after the introduction of bread fortified with iodised salt. The women were selected according to a multistage proportionate-to-size sampling design. Urine samples were collected and a general questionnaire was completed face to face with the study nurse. The median urinary iodine concentration (UIC) among pregnant women (n1311) was 124·1 μg/l and 122·6 μg/g creatinine when corrected for urinary creatinine. The median UIC in the first trimester (118·3 μg/l) was significantly lower than that in the third trimester (131·0 μg/l) but significantly higher than among non-pregnant women (84·8 μg/l). Iodine-containing supplement intake was reported by 60·8 % of the women and 57·4 % of the women took this supplement daily. The risk of iodine deficiency was significantly higher in younger women, in women not taking iodine-containing supplements, with low consumption of milk and dairy drinks and during autumn. Women with a higher BMI had a higher risk of iodine deficiency but the risk was lower in women who reported alcohol consumption. The median UIC during pregnancy indicates iodine deficiency in Belgium and some women are at a higher risk of deficiency. The current low iodine intake in women of childbearing age precludes the correction of iodine deficiency in pregnant women supplemented with multivitamins containing 150 μg iodine as recommended.


2021 ◽  
pp. 1-9
Author(s):  
Pedro Ferreira ◽  
Cátia Pinheiro ◽  
Cláudia Matta Coelho ◽  
Juliana Guimarães ◽  
Gonçalo Pereira ◽  
...  

Abstract The role of milk and dairy products in supplying iodine to pregnant women is unknown in Portugal. The aim of this study was to evaluate the association between milk and dairy product consumption and the iodine status of pregnant women in the IoMum cohort of the Oporto region. Pregnant women were recruited between 10 and 13 weeks of gestation, when they provided a spot urine sample and information on lifestyle and intake of iodine-rich foods. Urinary iodine concentration (UIC) was determined by inductively coupled plasma MS. A total of 468 pregnant women (269 iodine supplement users and 199 non-supplement users) were considered eligible for analysis. Milk (but not yogurt or cheese) intake was positively associated with UIC, in the whole population (P = 0·02) and in the non-supplement users (P = 0·002), but not in the supplement users (P = 0·29). In non-supplement users, adjusted multinomial logistic regression analysis showed that milk consumption <3 times/month was associated with a five times increased risk of having UIC < 50 µg/l when compared with milk consumption ≥2 times/d (OR 5·4; 95 % CI 1·55, 18·78; P = 0·008). The highest UIC was observed in supplement users who reported consuming milk once per d (160 µg/l). Milk, but not yogurt or cheese, was positively associated with iodine status of pregnant women. Despite the observed positive association, daily milk consumption may not be sufficient to ensure adequate iodine intake in this population.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 858
Author(s):  
Tedson Lukindo ◽  
Ray Masumo ◽  
Adam Hancy ◽  
Sauli E. John ◽  
Heavenlight A. Paulo ◽  
...  

Background: Deficient and excess iodine intake during pregnancy can lead to serious health problems. In Tanzania, information available on iodine status during pregnancy is minimal. The aim of this study was to assess the iodine status and its association with sociodemographic factors in pregnant women in the Mbeya region, Tanzania. Method: A cross sectional survey involving 420 pregnant women (n=420) aged between 15-49 years registered in antenatal care clinics was conducted. Data were collected via interviews and laboratory analysis of urinary iodine concentration (UIC). Results: Median UIC was 279.4μg/L (+/-26.1) to 1915μg/L. Insufficient iodine intake (UIC below 150μg/L) was observed in 17.14% of participants, sufficient intake in 24.29% and 58.57% had intakes above the recommended level (>250μg/L). Rungwe district council (DC) had the highest proportion of patients (27.9%) with low iodine levels, while Chunya and Mbarali DCs had the greatest proportion of those with UIC’s, over the WHO recommended level. Fish consumption and education status were associated with increased risk of insufficient iodine while individuals in Mbalali DC aged between 35-49 years were associated with increased risk of UIC above recommended level. Conclusion: Both deficient and excess iodine intake remains a public health problem, especially in pregnant women in Tanzania. Therefore, educational programs on iodine intake are needed to ensure this population has an appropriate iodine intake to prevent any health risks to the mother and the unborn child.


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