Randomized clinical trial comparing different iodine interventions in school children

Abstract

Objective: The purpose of this trial was to compare three different iodine interventions. Design: School children aged 8-10 years were randomized into one of three groups: group A was provided with iodized salt by researchers with an iodine concentration of 25 ppm; group B purchased iodized salt from the market; and group C was similar to group B with the exception that they were given iodized oil capsules containing 400 mg iodine at the beginning of the study. Salt iodine content was measured bimonthly for 18 months and indicators of iodine deficiency were measured at baseline and 6, 9, 12 and 18 months after randomization. Results: The prevalence of abnormal thyroid volumes, based on the World Health Organization (WHO) body surface area reference > 97th percentile, was 18% at baseline and declined to less than 5% by 12 months in groups A and C, and to 9% after 18 months in group B. Results for goitre by palpation were similar. The median urinary iodine was 94 mg l −1 at baseline and increased in all groups to > 200 mg l −1 at the 6-month follow-up. Conclusions: In this population of school children with initially a low to moderate level of iodine deficiency, the group receiving salt with 25 ppm (group A) was not iodine deficient on all indicators after 18 months of study. When the iodine content of the salt varied, such as in group B, by 18 months thyroid sizes had not yet achieved normal status.

Progress and challenges in eliminating iodine deficiency in Ethiopia: a systematic review

“…A study from Tanzania, where the prevalence of goiter used to be 25 %, showed that within 12 years of initiating USI, 84 % of the population consumes iodized salt, and 94.5 % of 6-12 year old children have normal sized thyroid glands [38]. Similarly, the GR of Chinese schoolchildren affected by mild IDD dropped from 18 to 5-9 % after just 18 months of salt iodization supplement [39]. According to a recent ICCIDD letter [15], African countries such as Burundi, Kenya, Nigeria, Uganda, Tunisia, Namibia, Zimbabwe and Libya have successfully achieved USI, and their coverage of households with iodized salt is more than 90 %.…”

Systematic review using meta-analyses to estimate dose-response relationships between iodine intake and biomarkers of iodine status in different population groups

“…Thirteen RCTs that assessed iodine intake and UI in children and adolescents were identified. Two papers reported data for boys and girls separately, two studies had two separate iodine intervention dose groups, and two studies had three iodine‐treated dose groups; therefore, 21 estimates were included in the analysis. These 21 estimates included a total of 3,397 participants with an age range of 4 to 16 years (Table ).…”

“…The median duration of the included studies was 12 weeks (range, 2–192 weeks). In four RCTs, iodine supplements were given in the form of potassium iodide, in doses that ranged from 100 to 1,500 μg/day. Iodized oil supplementation was used in 10 RCTs, with doses ranging from 120 to 960 mg/day.…”

“…Eight RCTs that assessed iodine intake and TSH concentration in children and adolescents were included. One study reported data for boys and girls separately, and one study had three groups treated with different doses of iodine, so 11 estimates with a total of 1,223 participants were included.…”

Use of iodized salt in the households improves the iodine status of pregnant women and school-age children in Donetsk, Ukraine: A double-blind randomized controlled trial

“…1). Это увеличение сходно с дан ными ранее проведенных исследований в других странах [19,37,38,41]. В этих исследованиях было обнаружено увеличение в уровня ЙМ пределах от 65 до 115 мкг/л через один год после использования в питании ЙС.…”