Comparison of Median Urinary Iodine Concentration as an Indicator of Iodine Status among Pregnant Women, School-Age Children, and Nonpregnant Women

Wong, Esther MF; Sullivan, Kevin M.; Perrine, Cria G.; Rogers, Lisa M.; Peña-Rosas, Juan Pablo

doi:10.1177/156482651103200304

Cited by 87 publications

(57 citation statements)

References 19 publications

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“…It should be noted that most of these countries with concordant results between pregnant women and the general population adopted salt iodization programmes a long time ago (Switzerland in 1922, USA in 1924, Bulgaria in 1958) (37) . In a recent literature review on iodine status which included surveys that took into account -as well as pregnant women and school-aged children -also pregnant women v. non-pregnant women, Wong et al came to the conclusion that the iodine status of pregnant women has to be addressed by considering pregnant women separately (38) .…”

Section: Discussionmentioning

confidence: 99%

Iodine and iron status of pregnant women in Lubumbashi, Democratic Republic of Congo

Habimana

Twite

Wallemacq

et al. 2013

Public Health Nutr.

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Objective: Adequate iodine and Fe intakes are imperative during pregnancy to prevent fetal defects, but such data are not available in the Democratic Republic of Congo. We aimed to assess iodine and Fe status in pregnant women from Lubumbashi. Design: Cross-sectional study. We measured urinary iodine concentration (UIC) in random urine samples using a modified Sandell-Kolthoff digestion method; the WHO reference medians were used to classify iodine intake as deficient, adequate, more than adequate or excessive. Serum ferritin concentrations were measured by immunoenzymatic assay and considered insufficient when ,12 ng/ml. Setting: Maternity units from rural, semi-urban and urban areas of Lubumbashi, Democratic Republic of Congo. Subjects: Two hundred and twenty-five randomly selected pregnant women attending prenatal consultation, seventy-five postpartum women and seventy-five non-pregnant women as controls. Results: Overall median UIC in pregnant women was 138 (interquartile range: 105-172) mg/l, indicating iodine deficiency, whereas postpartum and nonpregnant women had adequate iodine intake: median UIC 5 144 mg/l and 204 mg/l, respectively. Median UIC values were lower in late pregnancy than in early pregnancy: in the first, second and third trimester respectively 255 mg/l, 70 mg/l and 88 mg/l in the rural area; 306 mg/l, 166 mg/l and 68 mg/l in the semi-urban area; and 203 mg/l, 174 mg/l and 99 mg/l in the urban area. Fe was insufficient in 39 % of pregnant women compared with 21 % of non-pregnant and postpartum women. In the third trimester, deficiencies in both iodine and Fe were high: 40 %, 12 % and 18 % in the rural, semi-urban and urban areas, respectively. Conclusions: Our data suggest that pregnant women are at risk of iodine and Fe deficiencies in Lubumbashi. Country policies fighting against iodine and Fe deficiencies during pregnancy should be reinforced.

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Section: Discussionmentioning

confidence: 99%

Iodine and iron status of pregnant women in Lubumbashi, Democratic Republic of Congo

Habimana

Twite

Wallemacq

et al. 2013

Public Health Nutr.

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“…It has been discussed if urinary iodine excretion in nonpregnant adults and in schoolchildren is useful for the evaluation of iodine status in pregnant women living in the same area [19]. In our Danish study, we found no difference between the median UIC in pregnant women, their male partners and children when urine sampling was performed at home under similar conditions (fig.…”

Section: Methods To Evaluate Id In Pregnant Womenmentioning

confidence: 53%

Iodine Supplementation in Pregnancy and the Dilemma of Ambiguous Recommendations

Andersen¹,

Laurberg²

2016

Eur Thyroid J

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Iodine requirements are increased during pregnancy, predominantly caused by an increase in renal iodide clearance and in the use of iodine for thyroid hormone production. Because iodine deficiency (ID) in pregnancy may be associated with neurodevelopmental deficits in the offspring, a pertinent question is at what level of iodine intake pregnant women should be advised to take iodine-containing supplements. The consensus reached by the WHO/UNICEF/ICCIDD in 2007 was that pregnant women should not be recommended to take iodine-containing supplements if the population in general had been iodine sufficient for at least 2 years. However, guidance on this differs between scientific societies. This review discusses iodine supplementation in pregnancy. Based on current evidence, the recommendations given by WHO/UNICEF/ICCIDD in 2007 provide a valid guidance on the use of iodine supplements in pregnant women. Women living in a population with a median urinary iodine concentration (UIC) at or above 100 µg/l are not in need of iodine supplementation in pregnancy. On the other hand, if the population median UIC is below 100 µg/l, pregnant women should take iodine-containing supplements until the population in general has been iodine sufficient for at least 2 years by way of universal salt iodization.

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“…Based on median UIC, pregnant women were iodine sufficient but children had more-than-adequate iodine intake. A recent review concluded that when the median UIC in SAC or non-pregnant women indicated iodine intake was adequate or above requirements in a region, about half the time pregnant women in that same region had inadequate iodine intake (15) . Multiple studies have reported that when SAC have adequate iodine status (median UIC = 100-199 µg/l), pregnant women are deficient (median UIC < 150 µg/l), and that iodine sufficiency in pregnancy is attained only when the SAC have more-than-adequate (median UIC = 200-299 µg/l) iodine status (14,15,(25)(26)(27)(28) .…”

Section: Discussionmentioning

confidence: 99%

“…A recent review concluded that when the median UIC in SAC or non-pregnant women indicated iodine intake was adequate or above requirements in a region, about half the time pregnant women in that same region had inadequate iodine intake (15) . Multiple studies have reported that when SAC have adequate iodine status (median UIC = 100-199 µg/l), pregnant women are deficient (median UIC < 150 µg/l), and that iodine sufficiency in pregnancy is attained only when the SAC have more-than-adequate (median UIC = 200-299 µg/l) iodine status (14,15,(25)(26)(27)(28) . In an earlier Thai study using similar methodology (25) but in families where not all meals were consumed within the household, despite a median UIC of 200 μg/l in SAC, iodine intakes in pregnant women were inadequate, with a median UIC of only 108 μg/l.…”

Section: Discussionmentioning

confidence: 99%

The iodized salt programme in Bangalore, India provides adequate iodine intakes in pregnant women and more-than-adequate iodine intakes in their children

Jaiswal

Melse‐Boonstra

Sharma

et al. 2014

Public Health Nutr.

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Objective: To compare the iodine status of pregnant women and their children who were sharing all meals in Bangalore, India. Design: A cross-sectional study evaluating demographic characteristics, household salt iodine concentration and salt usage patterns, urinary iodine concentrations (UIC) in women and children, and maternal thyroid volume (ultrasound). Setting: Antenatal clinic of an urban tertiary-care hospital, which serves a low-income population. Subjects: Healthy pregnant women in all trimesters, aged 18-35 years, who had healthy children aged 3-15 years. Results: Median (range) iodine concentrations of household powdered and crystal salt were 55·9 (17·2-65·9) ppm and 18·9 (2·2-68·2) ppm, respectively. The contribution of iodine-containing supplements and multi-micronutrient powders to iodine intake in the families was negligible. Adequately iodized salt, together with small amounts of iodine in local foods, were providing adequate iodine during pregnancy: (i) the overall median (range) UIC in women was 172 (5-1024) µg/l; (ii) the median UIC was >150 µg/l in all trimesters; and (iii) thyroid size was not significantly different across trimesters. At the same time, the median (range) UIC in children was 220 (10-782) µg/l, indicating more-than-adequate iodine intake at this age. Median UIC was significantly higher in children than in their mothers (P = 0·008). Conclusions: In this selected urban population of southern India, the iodized salt programme provides adequate iodine to women throughout pregnancy, at the expense of higher iodine intake in their children. Thus we suggest that the current cut-off for median UIC in children indicating more-than-adequate intake, recommended by the WHO/UNICEF/International Council for the Control of Iodine Deficiency Disorders may, need to be reconsidered. Key words Iodine Iodized salt Urinary iodine concentration Pregnant women Children IndiaUniversal salt iodization (USI) is a mass fortification approach that is intended to cover the iodine requirements of all individuals in the population; it is estimated that 128 countries have established iodized salt programmes (1) .As USI programmes mature in many countries, greater emphasis is being placed on ensuring that USI meets the increased needs of pregnant women because of the risk of irreversible fetal brain damage due to iodine deficiency (2,3) . Another focus of mature programmes is the need for careful monitoring to avoid not only iodine deficiency but also iodine excess (1) . Median urinary iodine concentration (UIC) in school-aged children (SAC) and household access to adequately iodized salt based on national standards are routinely used as the primary indicator of the impact of USI programmes. However, the iodine requirement of SAC is disproportionately lower than that of pregnant women, which leaves only a narrow intake range to meet the needs of pregnant women without leading to more-than-adequate intake in children according to the current UIC cut-off of 200 μg/l (4) .

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Comparison of Median Urinary Iodine Concentration as an Indicator of Iodine Status among Pregnant Women, School-Age Children, and Nonpregnant Women

Cited by 87 publications

References 19 publications

Iodine and iron status of pregnant women in Lubumbashi, Democratic Republic of Congo

Iodine and iron status of pregnant women in Lubumbashi, Democratic Republic of Congo

Iodine Supplementation in Pregnancy and the Dilemma of Ambiguous Recommendations

The iodized salt programme in Bangalore, India provides adequate iodine intakes in pregnant women and more-than-adequate iodine intakes in their children

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