Long-term effect of iodized water and iodized oil supplementation on total goitre rate and nutritional status of school children in Ngargoyoso sub-district, Karanganyar regency, Central Java, Indonesia

Background: Ngargoyoso sub-district, Karanganyar regency, Central Java province, Indonesia, can be classified as severe IDD endemic area with TGR 51.9%. People get drinking water from spring-wells which contain no iodine. Drinking water has been distributed via pipelines directly to people’s home. Objectives: The ultimate goal of the study was to supplement people’s drinking water with iodine. The present study was designed to test hypothesis that iodine supplementation into drinking water was effective as iodized oil delivered in capsules. Methods: Eight hundred school children from year two and year four in Ngargoyoso sub-district were randomly assigned into two groups. The first group (N=407) received 100 mg iodine capsules (Yodiol™, Kimia Farma, Indonesia) and the second group (N=393) received 100 µg KIO3 daily via drinking water. Urinary iodine excretion (UIE) was measured using Method A (ammonium persulfate) in an accredited IDD Laboratory in Magelang, Central Java, Indonesia. Goitre prevalence was measured by palpation method. Total goitre rate (TGR) is the sum of grade 1 and grade 2. Nutritional status was measured as z-score of weight for age, height for age and weight for height using WHO Anthro (2005). Statistical analysis was performed using SPSS for Windows release 17.0 (Chicago, IL, USA). Results: Urinary iodine excretion increased in both groups. In the capsule group there was an increase of UIE from 244.16 (±104.37) µg/L to 522.91(±315.83) µg/L (p<0.001), whereas UIE in the KIO3 group slightly increased from 210/94 (±201.45) µg/L to 225.70 (±93.28) µg/L (p<0.05). Total goitre rate (TGR) decreased from 51.9% at basal to 46.19% and 38.5% after three months and six months supplementation in the capsule group. While in the KIO3 group TGR decreased to 42.49% and 34.35% after three and six months, respectively. Comparison between groups showed no significant differences in TGR (p>0.05). Nutritional status was not affected by iodine supplementation in both groups. Conclusion: Iodine supplementation into drinking water was effective as iodized oil in capsule in reducing goitre prevalence among school children in Ngargoyoso sub-district, Karanganyar regency, Central Java Province, Indonesia. Keywords: iodized water, iodized oil, goitre prevalence, nutritional status