title: Evaluation and monitoring of iodine deficiency disorders in school children in north-east Thailand.
abstract: The possibility of improving iodine deficiency disorder (IDD) in school children in Khon Kaen province was investigated during the period of 1 year, using an operational research approach. Four schools in Pupaman and Srichompu districts, namely Ban Khoa Wong, Na Fai Witaya, Ban Pa Num Tieng and Ban Non Khom, were selected for this study. Ban Non Khom served as the control school. Different methods were used for iodine fortification. Iodized salt was used for the children of the Ban Khoa Wong school, iodized water was used for Na Fai Witaya school and iodized fish sauce was used for Ban Pa Num Tieng school. The iodized salt, water and fish sauce were provided with the help of the school teachers under the supervision and advice of the team of investigators. Urine iodine excretion as well as palpation of the thyroid gland and the thyroid hormones T4, T3 and TSH were selected for monitoring and evaluation. The proportion of children with low urine iodine excretion, indicated by a cut-off point suggested by the WHO/ICCIDD/UNICEF working group, decreased during the course of the project in all schools receiving iodine supplementation as well as in the control school. However, the decrease was less in the control school in comparison with the implementation schools. Furthermore, the goitre rate decreased in all schools under investigation. The decrease of the goitre rate for the children of the control school might have been due to the activities of a village health volunteer from a nearby village who was using iodized salt for IDD control according to the ongoing national programme initiated by the Ministry of Public Health. No significant difference in the level of thyroid hormones was detected before or at the end of the supplementation for either the experimental schools or the control school. The results from the determination of thyroid hormone serum levels could not be used for assessing the outcome of the project. The measuring of urinary iodine excretion might be helpful in monitoring the iodine intake during the intervention phase. Long-term effects of iodine fortification could be seen best by the declining proportion of children with goitre. However, an observation of 1 year might not have been enough to clearly see the outcome of the project. The other possible contributing error to this study is intra-observer variation of the palpation technique when the sample size was not big enough. Goitrogens in this area might be another risk factor for the high prevalence rate of goitre. Further study in this field should be encouraged. The results of the study indicate that iodine fortification of salt and fish sauce is more effective than iodine fortification of drinking water. Due to the local preference of adding fish sauce (nam pla) instead of salt to almost all dishes, fish sauce proved to be the best vehicle for iodine fortification. The success of the project depended heavily on the understanding and cooperation of the school teachers and the school children. Major constraints in conducting this project were the insufficient distribution of iodized salt and potassium iodide solution for the fortification of drinking water, and the inconsistency of iodide concentration in the salt after fortification.
authors.affiliation: Department of Tropical Nutrition and Food Science, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
authors.forename: P
authors.initials: P
authors.lastname: Pongpaew
authors.forename: R
authors.initials: R
authors.lastname: Tungtrongchitr
authors.forename: V
authors.initials: V
authors.lastname: Supawan
authors.forename: N
authors.initials: N
authors.lastname: Vudhivai
authors.forename: P
authors.initials: P
authors.lastname: Sanchaisuriya
authors.forename: C
authors.initials: C
authors.lastname: Intarakhao
authors.forename: U
authors.initials: U
authors.lastname: Mahaweerawat
authors.forename: B
authors.initials: B
authors.lastname: Phonrat
authors.forename: P
authors.initials: P
authors.lastname: Jotking
authors.forename: W
authors.initials: W
authors.lastname: Kongdee
authors.forename: F P
authors.initials: FP
authors.lastname: Schelp
authors.forename: S
authors.initials: S
authors.lastname: Saowakhontha