Iodine deficiency status and iodised salt consumption in Malaysia: findings from a national iodine deficiency disorders survey

A nationwide cross-sectional school-based survey was undertaken among children aged 8-10 years old to determine the current iodine deficiency status in the country. Determination of urinary iodine (UI) and palpation of the thyroid gland were carried out among 18,012 and 18,078 children respectively while iodine test of the salt samples was done using Rapid Test Kits and the iodometric method. The results showed that based on WHO/ ICCIDD/UNICEF criteria, the national median UI was 109 μg/L [25th, 75th percentile (67, 166)] showing borderline adequacy. The overall national prevalence of iodine deficiency disorders (IDD) with UI<100 μg/L was 48.2% (95% CI: 46.0, 50.4), higher among children residing in rural areas than in urban areas. The highest prevalence of UI<100 μg/L was noted among the aborigines [(81.4% (95% CI: 75.1, 86.4)]. The national total goitre rate (grade 1 and grade 2 goitre) was 2.1%. Of 17,888 salt samples brought by the school children, 28.2% (95% CI: 26.4, 30.2) were found to have iodine content. However, the overall proportion of the households in Malaysia using adequately iodised salt as recommended by Malaysian Food Act 1983 of 20-30 ppm was only 6.8% (95% CI: 5.1, 9.0). In conclusion, although a goitre endemic was not present in Malaysia, almost half of the states in Peninsular Malaysia still have large proportion of UI level <100 μg/L and warrant immediate action. The findings of this survey suggest that there is a need for review on the current approach of the national IDD prevention and control programme.