Dataset Information

Inadequate iodine intake in lactating women in Sweden: A pilot 1-year, prospective, observational study.

ABSTRACT:

Introduction

Breastfed infants depend on breast-milk iodine for growth and brain development, as iodine is a trace element important for thyroid hormone production. Iodine need is higher during lactation; hence, mothers and children are at risk of iodine deficiency. We aimed to explore maternal iodine and thyroidal status during lactation.

Material and methods

Pregnant women were recruited in Gothenburg, southwest Sweden. Maternal urine and serum were collected at pregnancy week 35-37 (n = 84) and 0.5, 4, and 12 months postpartum. Seventy mothers provided breast milk at 0.5 months.

Results

Median (interquartile range) breast-milk iodine concentration was 90 (66-116) ?g/L. About 58% had breast-milk iodine concentration <100 ?g/L. Iodine supplement users (n = 13) had higher breast-milk iodine concentration than non-users (n = 49) (140 ?g/L vs 71 ?g/L, P = .001). Exclusively breastfeeding women at 4 months postpartum (n = 57) had lower median urinary iodine concentration (85 ?g/L vs 133 ?g/L, P = .004) and higher thyroglobulin serum concentration (22.3 ?g/L vs 11.8 ?g/L, P = .032) than non-exclusively breastfeeding women (n = 25). Concentrations of thyroid hormones were unaffected.

Conclusions

This pilot study suggests that lactating women in southwest Sweden present mildly inadequate iodine intake, mainly among non-iodine supplement users and exclusively breastfeeding mothers. Studies on the coverage of the iodine fortification program in breastfeeding women are warranted.

SUBMITTER: Manousou S

PROVIDER: S-EPMC7756844 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Publications

Inadequate iodine intake in lactating women in Sweden: A pilot 1-year, prospective, observational study.

Manousou Sofia S Augustin Hanna H Eggertsen Robert R Hulthén Lena L Filipsson Nyström Helena H

Acta obstetricia et gynecologica Scandinavica 20200917 1

<h4>Introduction</h4>Breastfed infants depend on breast-milk iodine for growth and brain development, as iodine is a trace element important for thyroid hormone production. Iodine need is higher during lactation; hence, mothers and children are at risk of iodine deficiency. We aimed to explore maternal iodine and thyroidal status during lactation.<h4>Material and methods</h4>Pregnant women were recruited in Gothenburg, southwest Sweden. Maternal urine and serum were collected at pregnancy week 3 ...[more]

PMID: 32880886

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Project description:BackgroundUS iodine intake, estimated from the median urinary iodine concentration of population representative data, has declined by half since the 1970s, which is problematic because maternal iodine intake is critical for fetal neurodevelopment. Relying on median urinary concentrations to assess iodine intake of populations is standard practice but does not describe the number of individuals with insufficient intake. Prevalence estimates of inadequate and excessive intake are better for informing public health applications but require multiple urine samples per person; such estimates have been generated in pediatric populations but not yet among pregnant women.ObjectiveOur aims were as follows: (1) to assess median urinary iodine concentrations across pregnancy for comparison with national data and (2) to estimate the prevalence of inadequate and excessive iodine intake among pregnant women in mid-Michigan.Study designData were collected from 2008 to 2015 as part of a prospective pregnancy cohort in which women were enrolled at their first prenatal clinic visit. Few exclusion criteria (<18 years or non-English speaking) resulted in a sample of women generally representative of the local community, unselected for any specific health conditions. Urine specimens were obtained as close as practicable to at least 1 specimen per trimester during routine prenatal care throughout pregnancy (n=1-6 specimens per woman) and stored at -80°C until urinary iodine was measured to estimate the iodine intake (n=1014 specimens from 464 women). We assessed urinary iodine across pregnancy by each gestational week of pregnancy and by trimester. We used multiple urine specimens per woman, accounted for within-person variability, performed data transformation to approximate normality, and estimated the prevalence of inadequate and excessive iodine intake using a method commonly employed for assessment of nutrient status.ResultsMaternal characteristics reflected the local population in racial and ethnic diversity and socioeconomic status as follows: 53% non-Hispanic white, 22% non-Hispanic black, and 16% Hispanic; 48% had less than or equal to high school education and 71% had an annual income of <$25,000. Median urinary iodine concentrations in the first, second, and third trimester-including some women contributing more than 1 specimen per trimester-were 171 μg/L (n=305 specimens), 181 μg/L (n=366 specimens), and 179 μg/L (n=343 specimens), respectively, with no significant difference by trimester (P=.50, Kruskal-Wallis test for equality of medians). The estimated prevalence of inadequate and excessive iodine intake was 23% and <1%, respectively.ConclusionMedian urinary iodine concentrations in each trimester were above the World Health Organization cutoff of 150 μg/L, indicating iodine sufficiency at the group level across pregnancy. However, the estimated prevalence of inadequate iodine intake was substantial at 23%, whereas prevalence of excessive intake was <1%, indicating a need for at least some women to increase consumption of iodine during pregnancy. The American Thyroid Association, the Endocrine Society, and the American Academy of Pediatrics recommend that all pregnant and lactating women receive a daily multivitamin or mineral supplement that contains 150 μg of iodine. The data presented here should encourage the collection of similar data from additional US population samples for the purpose of informing the American College of Obstetricians and Gynecologists' own potential recommendations for prenatal iodine supplementation.

Project description:BackgroundObesity and cardiovascular diseases are increasing globally and any association between reproduction and these conditions is of concern. Unfortunately, little is known about normal levels of metabolic risk factors in women of different body mass index throughout the reproductive cycle. This study is one of the first to describe the metabolic risk profile of lactating overweight or obese women at 8-12 weeks postpartum.MethodsDuring 2007-2009, 66 overweight or obese Swedish lactating women without known diseases underwent detailed measurements of their metabolic profiles, dietary intake and general health before entering a lifestyle intervention trial. Baseline measurements took place between 8-12 wk postpartum. Almost all women were exclusively breastfeeding their term infants.ResultsThe women were regarded as healthy, as reflected in the absence of diagnosed diseases, their own perceptions and in normal hemoglobin, albumin and fasting plasma glucose values. Four women were diagnosed with metabolic syndrome. In these cases, underlying conditions included large waist circumference, low HDL cholesterol values, high triglyceride values and relatively high blood pressure. The metabolic profile differed between overweight and obese women; obese women had significantly higher levels of fasting insulin (p = 0.017), borderline higher HOMA values (p = 0.057) and significantly higher triglyceride values (p = 0.029), as well as larger waist and hip circumferences (p<0.001 and p<0.001). However, no significant differences between overweight and obese women were detected for LDL or total cholesterol levels. Overweight and obese women reported similar total energy and macronutrient intakes, but obese women tended to be less physically active (p = 0.081).ConclusionsAmong generally healthy lactating women, obesity as compared to overweight is associated with increased metabolic risk. This cut-off is thus important also in the early postpartum period, and obesity among these women should warrant proper health investigation. Macronutrient intake did not differ between the groups and, hence, cannot explain these differences.Trial registrationClinicalTrials.gov Identifier: NCT01343238.

Project description:BACKGROUND:Studies indicate that mild to moderate iodine deficiency in pregnancy may have a long-term negative impact on child neurodevelopment. These effects are likely mediated via changes in maternal thyroid function, since iodine is essential for the production of thyroid hormones. However, the impact of iodine availability on thyroid function during pregnancy and on thyroid function reference ranges are understudied. The aim of this study was to investigate the association between iodine intake and thyroid function during pregnancy. DESIGN:In a population-based pregnancy cohort including 2910 pregnant women participating in The Norwegian Mother and Child Cohort Study, we explored cross sectional associations of maternal iodine intake measured (1) by a food frequency questionnaire and (2) as iodine concentration in a spot urine sample, with plasma thyroid hormones and antibodies. RESULTS:Biological samples were collected in mean gestational week 18.5 (standard deviation 1.3) and diet was assessed in gestational week 22. Median iodine intake from food was 121??g/day (interquartile range 90, 160), and 40% reported use of iodine-containing supplements in pregnancy. Median urinary iodine concentration (UIC) was 59??g/L among those who did not use supplements and 98??g/L in the women reporting current use at the time of sampling, indicating mild to moderate iodine deficiency in both groups. Iodine intake as measured by the food frequency questionnaire was not associated with the outcome measures, while UIC was inversely associated with FT3 (p?=?0.002) and FT4 (p?<?0.001). Introduction of an iodine-containing supplement after gestational week 12 was associated with indications of lower thyroid hormone production (lower FT4, p?=?0.027, and nonsignificantly lower FT3, p?=?0.17). The 2.5th and 97.5th percentiles of TSH, FT4, and FT3 were not significantly different by groups defined by calculated iodine intake or by UIC. CONCLUSION:The results indicate that mild to moderate iodine deficiency affect thyroid function in pregnancy. However, the differences were small, suggesting that normal reference ranges can be determined based on data also from mildly iodine deficient populations, but this needs to be further studied. Introducing an iodine-containing supplement might temporarily inhibit thyroid hormone production and/or release.

Project description:BackgroundPatients with rheumatoid arthritis (RA), who suffer from impaired physical function and fatigue, may have difficulties with grocery shopping and preparing meals. Also, to improve symptoms, patients often experiment with diets but seldom consult a dietitian. Although this could lead to a nutritiously deprived diet, an up-to-date, thorough description of the nutrient intake in Swedish patients with RA is absent. Here, we investigated the habitual dietary energy and nutrient intake in patients with RA living in southwestern Sweden.Materials and methodsThree-day food records performed at two time points during the ADIRA (Anti-inflammatory Diet In Rheumatoid Arthritis) trial, were used. The intake of energy and nutrients was analyzed using The Swedish Food Composition Database.ResultsA total of 62 participants (50 females, 12 males) were included in the study, where 18 participants completed one 3-day food record and 44 participants completed two 3-day food records. Median (IQR) intake of total fat was above or in the upper range of recommendations (females: 37.1 [32.5, 41.7] energy percent (E%), and males: 40.3 [37.5, 42.9] E%). Median (IQR) intake of saturated fatty acids exceeded recommendations (females: 14.9 [12.5, 17.0] E% and males: 15.4 [12.2, 17.0] E%), while median (IQR) carbohydrate and fiber intakes were below recommendations (females: 41.7 [36.3, 45.4] E% and 17.2 [12.8, 20.9] g, respectively, and males: 38.8 [35.2, 40,3] E% and 18.5 [15.7, 21.0] g, respectively). The reported intake of other macronutrients was in line with recommendations. For several micronutrients, e.g., vitamin A and D, folate, and calcium, median intake was below recommended intake. Vitamin A intake was especially low and did not reach lower intake level (LI) for 14 and 17% of females and males, respectively. For females, about 10% did not reach LI for vitamin D, calcium, and riboflavin.ConclusionWe found that patients with RA residing in southwestern Sweden reported a high intake of saturated fatty acids and low intake of fiber and several micronutrients.Clinical trial registration[https://clinicaltrials.gov/ct2/show/NCT02941055?term=NCT02941055&draw=2&rank=1], identifier [NCT02941055].

Project description:PurposePregnant women in Sweden are mildly iodine deficient. We investigated the effect of daily iodine supplementation on the iodine and thyroid status of pregnant women.MethodsIn this pilot, randomized, double-blind trial, 200 thyroid-healthy pregnant women were recruited at mean (standard deviation) pregnancy week 8.85 (1.62) and assigned (1:1) to daily intake of a multivitamin tablet with or without 150 μg of iodine. Urine and serum samples were collected at baseline and once during the second and third trimesters. Urinary iodine concentration (UIC), serum thyroglobulin (Tg), thyroid-stimulating hormone (TSH), free thyroxine (FT4), and thyroid peroxidase antibodies (TPOabs) were analyzed. Neonatal TSH data were collected. UIC and Tg were also analyzed in a group of 89 thyroid-healthy non-pregnant women of reproductive age (WRA).ResultsAt baseline, the intervention and the control groups had similar median UIC (interquartile range (IQR)): 110 μg/L (74-119) and 111 μg/L (66-168), respectively. The intervention group reached iodine sufficiency with median UIC (IQR) 139 μg/L (89-234) and 136 μg/L (91-211) in the second and third trimester, respectively, without significant difference from the lower limit of the recommended range, i.e. 150-250 μg/L (p = 0.42 and p = 0.87, respectively). The intervention group had higher median UIC and lower median Tg compared to the control group during the second (p < 0.001 and p = 0.019, respectively) and third trimester (p < 0.001 and p = 0.003, respectively), whereas thyroid hormones, serum TPOabs, and neonatal TSH were similar. The WRA group presented median UIC (IQR) 65 μg/L (30-98) and median Tg (IQR) 18 μg/L (13-27).ConclusionA daily supplement containing 150 μg of iodine to a group of pregnant women with mild iodine deficiency improved the iodine status from mild ID to iodine sufficiency. This improvement seems to have had a positive impact on maternal thyroglobulin. This study is now under extension to investigate the children's neuropsychological development.Trial registrationClinicalTrials.gov Identifier NCT02378246, May 3, 2015, retrospectively registered.

Dataset Information

Inadequate iodine intake in lactating women in Sweden: A pilot 1-year, prospective, observational study.

Introduction

Material and methods

Results

Conclusions

Publications

Inadequate iodine intake in lactating women in Sweden: A pilot 1-year, prospective, observational study.

Similar Datasets

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