Methods of assessment of iodine status in humans: a systematic review

Several reviews and meta-analyses have examined the effects of iodine on mental development. None focused on young children, so they were incomplete in summarizing the effects on this important age group. The current systematic review therefore examined the relationship between iodine and mental development of children 5 years old and under. A systematic review of articles using Medline (1980–November 2011) was carried out. We organized studies according to four designs: (1) randomized controlled trial with iodine supplementation of mothers; (2) non-randomized trial with iodine supplementation of mothers and/or infants; (3) prospective cohort study stratified by pregnant women’s iodine status; (4) prospective cohort study stratified by newborn iodine status. Average effect sizes for these four designs were 0.68 (2 RCT studies), 0.46 (8 non-RCT studies), 0.52 (9 cohort stratified by mothers’ iodine status), and 0.54 (4 cohort stratified by infants’ iodine status). This translates into 6.9 to 10.2 IQ points lower in iodine deficient children compared with iodine replete children. Thus, regardless of study design, iodine deficiency had a substantial impact on mental development. Methodological concerns included weak study designs, the omission of important confounders, small sample sizes, the lack of cluster analyses, and the lack of separate analyses of verbal and non-verbal subtests. Quantifying more precisely the contribution of iodine deficiency to delayed mental development in young children requires more well-designed randomized controlled trials, including ones on the role of iodized salt.

https://www.mdpi.com/2072-6643/5/4/1384/pdf

Iodine and Mental Development of Children 5 Years Old and Under: A Systematic Review and Meta-Analysis

A systematic review was conducted to evaluate the status and intake of iron, vitamin A, iodine, folate and zinc in women of reproductive age (WRA) (≥15–49 years) and pregnant women (PW) in Ethiopia, Kenya, Nigeria and South Africa. National and subnational data published between 2005 and 2015 were searched via Medline, Scopus and national public health websites. Per micronutrient, relevant data were pooled into an average prevalence of deficiency, weighted by sample size (WAVG). Inadequate intakes were estimated from mean (SD) intakes. This review included 65 surveys and studies from Ethiopia (21), Kenya (11), Nigeria (21) and South Africa (12). In WRA, WAVG prevalence of anaemia ranged from 18–51%, iron deficiency 9–18%, and iron deficiency anaemia at 10%. In PW, the prevalence was higher, and ranged from 32–62%, 19–61%, and 9–47%, respectively. In WRA, prevalence of vitamin A, iodine, zinc and folate deficiencies ranged from 4–22%, 22–55%, 34% and 46%, while in PW these ranged from 21–48%, 87%, 46–76% and 3–12% respectively. Inadequate intakes of these micronutrients are high and corresponded with the prevalence figures. Our findings indicate that nationally representative data are needed to guide the development of nutrition interventions and public health programs, such as dietary diversification, micronutrient fortification and supplementation.

https://www.mdpi.com/2072-6643/9/10/1096/pdf

Micronutrient Status and Dietary Intake of Iron, Vitamin A, Iodine, Folate and Zinc in Women of Reproductive Age and Pregnant Women in Ethiopia, Kenya, Nigeria and South Africa: A Systematic Review of Data from 2005 to 2015

Iodine deficiency is severe public health problem in Ethiopia. Although urinary iodine excretion level (UIE) is a better indicator for IDD the goitre rate is commonly used to mark the public health significance. The range of ill effect of IDD is however beyond goitre in Ethiopia. In this study the prevalence of goitre and its association with reproductive failure, and the knowledge of women on Iodine Deficiency were investigated. A cross-section community based study was conducted during February to May 2005 in 10998 women in child bearing age of 15 to 49 years. To assess the state of iodine deficiency in Ethiopia, a multistage "Proportional to Population Size" (PPS) sampling methods was used, and WHO/UNICEF/ICCIDD recommended method for goitre classification. Total goitre prevalence (weighted) was 35.8% (95% CI 34.5–37.1), 24.3% palpable and 11.5% visible goitre. This demonstrates that more than 6 million women were affected by goitre. Goitre prevalence in four regional states namely Southern Nation Nationalities and People (SNNP), Oromia, Bebshandul-Gumuz and Tigray was greater than 30%, an indication of severe iodine deficiency. In the rest of the regions except Gambella, the IDD situation was mild to moderate. According to WHO/UNICEF/ICCIDD this is a lucid indication that IDD is a major public health problem in Ethiopia. Women with goitre experience more pregnancy failure (X2 = 16.5, p < 0.001; OR = 1.26, 1.12 < OR < 1.41) than non goitrous women. Similarly reproductive failure in high goitre endemic areas was significantly higher (X2 = 67.52; p < 0.001) than in low. More than 90% of child bearing age women didn't know the cause of iodine deficiency and the importance of iodated salt. Ethiopia is at risk of iodine deficiency disorders. The findings presented in this report emphasis on a sustainable iodine intervention program targeted at population particularly reproductive age women. Nutrition education along with Universal Salt Iodization program and iodized oil capsule distribution in some peripheries where iodine deficiency is severe is urgently required.

/pdf/the-goitre-rate-its-association-with-reproductive-failure-pgt6bz3gp3.pdf

The goitre rate, its association with reproductive failure, and the knowledge of iodine deficiency disorders (IDD) among women in Ethiopia: cross-section community based study

Objective:To perform a systematic review to evaluate iron, vitamin A, zinc, and iodine status and intakes in children and adolescents (0-19 years) in Ethiopia, Kenya, Nigeria, and South Africa.Method:Both national and subnational data published from the year 2005 to 2015 were searched via MEDLINE, Scopus, and national public health websites. For each micronutrient and country, status data from relevant studies and surveys were combined into an average prevalence and weighted by sample size (WAVG). Inadequate intakes were estimated from mean (SD) intakes.Results:This review included 55 surveys and studies, 17 from Ethiopia, 11 from Kenya, 12 from Nigeria, and 16 from South Africa. The WAVG prevalence of anemia ranged from 25% to 53%, iron deficiency from 12% to 29%, vitamin A deficiency (VAD) from 14% to 42%, zinc deficiency from 32% to 63%, and iodine deficiency from 15% to 86% in children aged 0 to 19 years from 4 countries. Generally, children <5 years had higher prevalence of anemia (32%-63%), VAD (15%...

https://journals.sagepub.com/doi/pdf/10.1177/0379572117715818

Are Low Intakes and Deficiencies in Iron, Vitamin A, Zinc, and Iodine of Public Health Concern in Ethiopian, Kenyan, Nigerian, and South African Children and Adolescents?

Background : More than two billion individuals worldwide have inadequate iodine intake and the adverse consequences of iodine deficiency are widely observed Objective : To assess the iodine status of primary school children and the knowledge of iodine deficiency disorders among their caretakers Methods : A cross-sectional study was conducted in Hawassa Town, Southern Ethiopia The study participants were school children (n=116) aged 7-9 years A two-stage sampling method was used to select participants Goiter and urinary iodine concentration were measured in the children to evaluate their iodine status Socioeconomic characteristics, dietary patterns and caretaker knowledge of iodine deficiency were assessed by using questionnaires Household salt iodine concentration was also measured Results : Total goiter rate was 136% and was significantly associated with age [AOR=134 (32-557)] Eighty two percent of the children had urinary iodine concentration below 50 ig/L, indicating the presence of moderate iodine deficiency None of the households were using adequately iodized salt More than half of the respondents did not know about the importance of iodized salt Conclusion : The observed degree of iodine deficiency in children and the limited knowledge about iodine in an urban area such as Hawassa stress the urgent need for implementing interventions to combat iodine deficiency [Ethiop J Health Dev 2012;26(1):30-35]

/pdf/iodine-deficiency-in-primary-school-children-and-knowledge-25h1phqnbl.pdf

Iodine deficiency in primary school children and knowledge of iodine deficiency and iodized salt among caretakers in Hawassa Town: Southern Ethiopia

OBJECTIVE Iodine deficiency is one of the most common micronutrient deficiencies worldwide and is a major cause of preventable mental retardation. The purpose of this study was to assess the iodine status and cognitive function of women of childbearing age and their five-year-old children. METHOD A cross-sectional study was conducted in a rural village in southern Ethiopia. A convenience sample of one hundred women and their five year-old children participated in the study. Goiter grade, urinary iodine excretion, Raven's CPM and cognitive tests from the Kaufman ABC-II, were administered to the women and their children. RESULTS The use of iodized salt was only 2%. The mean iodine content of water in and around the study area was 4.46 microg/l. Occurrence of goiter was 85% in the women and 33% in children. Urinary iodine excretion for all participants was <49 microg/L, the top of the range for moderate iodine deficiency. The median urinary iodine excretion (UIE) was 1 microg/L for both mothers and children. For children, measures of short term memory (Sequential index) were correlated with the visual processing (Simultaneous index) (r = 0.49, p < 0.0001). Goiter and urinary iodine excretion were correlated to Sequential index (r = 0.39, p = 0.0011 and r = 0.2, p = 0.05) respectively, but not to the Simultaneous index for children. Sequential (r = 0.21, p = 0.03) and Simultaneous (r = 0.29, p = 0.004) indices of mothers and children were correlated. CONCLUSION The high prevalence of goiter and the low urinary iodine excretion demonstrate serious long- and short-term iodine deficiency in the study area. Relations between measures of iodine status and short term memory in children raise concern about potential functional effects of iodine deficiency.

Iodine status and cognitive function of women and their five year-old children in rural Sidama, southern Ethiopia.

Background Maternal iodine nutrition during pregnancy is critical and deficiency during this period may compromise optimal fetal development. Objective To determine iodine status and knowledge of iodine deficiency disorders (IDD) of pregnant women in rural Sidama, southern Ethiopia. Methods A cross-sectional community-based study was conducted in three kebeles which were selected randomly from the eight kebeles in the study area using probability proportional to size methods. Data were collected in January, 2009, from 172 pregnant women. Main outcome measures were urinary iodine concentration (UIC), % of population with UIC Results Median UIC was only 15 microg/L compared to the 150 microg/L minimum recommendation from WHO/UNICEF/ ICCIDD for pregnant women. The UIC of 60% of the women was 90% of participants didn't know about IDD, about the cause of goiter or why iodized salt is important. Conclusion Results indicated the presence of severe iodine deficiency in the study population; urgent intervention, through universal salt iodization, and iodine supplementation to high risk groups is required.

Clinical assessment of goiter and low urinary iodine concentration depict presence of severe iodine deficiency in pregnant Ethiopian women: a cross-sectional study in rural Sidama, southern Ethiopia.

Clinical Assessment of Goiter and Low Urinary Iodine Concentration Depict Presence of Severe Iodine Deficiency in Pregnant Ethiopian Women: A Cross-sectional Study in Rural Sidama, Southern Ethiopia

A longitudinal study was conducted during 1994 - 1996 among elementary school children aged 6-14 years in Awassa, South Ethiopia The aim of the study was to compare the efficacy of varying doses of oral iodized oil (200mg and 400mg) on thyroid function The study included clinical examination of goitre, biochemical tests for thyroid function, and assessment of nutritional status of the children A total of 110 children were randomly selected from six elementary schools and randomly assigned into high or 400mg (n=53) and low or 200 mg (n=57) dose groups for administration After 13 months of intervention 42% goitre reduction was noted in the 200mg group while 49% regress of goitre was observed in the 400mg group The difference was not statistically significant (p>005) There were no significant differences (p>005) in serum concentrations of T3, T4 and TSH between the two dose groups before or after administration These clearly indicate that the two graded doses of oral iodized oil have the same effect on thyroid function and goitre reduction 
(Ethiopian Journal of Health Development: 2000, 14(1): 49-66)

https://www.ajol.info/index.php/ejhd/article/download/9930/31210

Cherinet Abuye

Papers

Iodine deficiency in primary school children and knowledge of iodine deficiency and iodized salt among caretakers in Hawassa Town: Southern Ethiopia

Iodine status and cognitive function of women and their five year-old children in rural Sidama, southern Ethiopia.

Clinical assessment of goiter and low urinary iodine concentration depict presence of severe iodine deficiency in pregnant Ethiopian women: a cross-sectional study in rural Sidama, southern Ethiopia.

Clinical Assessment of Goiter and Low Urinary Iodine Concentration Depict Presence of Severe Iodine Deficiency in Pregnant Ethiopian Women: A Cross-sectional Study in Rural Sidama, Southern Ethiopia

Thyroid responses to varying doses of oral iodized oil in school children in Awassa, Ethiopia