A universal salt iodization (USI) was introduced in Sarawak, Malaysia in 2008 to control the iodine deficiency disorders (IDD) among its population. The purpose of this study is to evaluate the impact of the USI among school children in Sarawak after 10 years of implementation. The data were extracted from 2008 and 2018 Sarawak state-wide IDD surveys. Briefly, both surveys were cross-sectional surveys covering information on the socio-demographic, status of goitre, urinary iodine, and the amount of iodine in the salt samples. A total of 1104 and 988 between the ages of 8 and 10 were involved in the 2008 and 2018 surveys, respectively. The overall prevalence of goitre among the school children in Sarawak was significantly lower in 2018 (0.1%) compared to 2008 (2.9%). The median urinary iodine concentration (UIC) in urine samples had risen significantly from 102.1 µg/L in 2008 to 126.0 µg/L in 2018. In terms of iodine content in salt samples, the median concentration improved significantly in 2018 (35.5 µg/L) compared to 2008 (14.7 µg/L). After 10 years of USI implementation in Sarawak, the results from both surveys confirmed the effectiveness of mandatory USI in increasing the nutritional iodine status of school children in Sarawak.

Previous findings from a state-wide Iodine Deficiency Disorders (IDD) study among pregnant women (PW) in Sarawak indicated that PW are at risk of IDD and further study is needed. This paper describes the methodology used in conducting this study on assessment of risk of iodine deficiency among pregnant women in Sarawak, Malaysia. Thirty maternal child health care clinics (MCHCs) were selected using probability proportional to population size (PPS) sampling technique. The PW sample size was calculated based on 95% confidence interval (CI), relative precision of 5%, design effect of 2, anticipated IDD prevalence of 65.0% and non-response rate of 20%. Thus, the total sample size required was 750 (25 respondents per selected MCHC). The WHO Expanded Programme on Immunization (EPI) surveys approach was used to randomly select the first respondent and subsequent respondents were chosen until the required number of PW was met. The required data were obtained through: face-to-face interviews (socio-demographic and food frequency questionnaire), clinical assessments (thyroid size, and hyper/hypothyroidism) and biochemical analysis (urine and blood serum). A total of 677 PW responded in the study with a response rate of 90.2%. Majority of the PW were at second gravida, aged 25-29 years old and of Malay ethnicity. The methodology used in this study was based on international guidelines which may provide state’s estimates. All the necessary steps were taken into consideration to ensure valid and reliable findings on current iodine status among PW.

Introduction: Iodine deficiency disorders (IDD) during pregnancy may impair the neurological development of the fetus. The aim of this study is to determine the iodine status among pregnant women (PW) in Sarawak after introduction of mandatory universal salt iodisation (USI) for seven years. Methods: A total of 508 first trimester PW attending government Maternal and Child Health Care clinics in all 11 divisions in Sarawak between 1st April and 15th June 2015 were recruited. Urine samples were obtained and analysed for urinary iodine concentration (UIC) using the modified Sandell-Kolthoff reaction method. For pregnant women, an adequate iodine intake was defined as a median UIC between 150-249 µg/L according to the WHO/UNICEF/ICCIDD’s criterion. For further analyses, the 11 divisions were then combined into 3 regions, namely Northern (Miri, Bintulu, Limbang), Central (Kapit, Mukah, Sibu, Sarikei, Betong) and Southern (Kota Samarahan, Kuching, Sri Aman). Results: The median UIC of the PW in Sarawak was 105.6 µg/L, indicating iodine deficiency. A total of 330 (65.0%) PW had UIC<150 µg/L. In terms of urinary iodine levels by region, the median UIC in Northern, Central and Southern regions were 136.3 µg/L, 85.5 µg/L and 97.4 µg/L respectively. The differences in median UIC between regions were significant. In addition, the Northern region (p = 0.001), Malay/Melanau ethnicity (p = 0.015) and parous parity (p = 0.014) were significantly associated with higher median UIC. No significant association was found for locality, age nor gravida. Conclusions: This study indicates inadequate iodine status among PW in Sarawak despite seven years of mandatory USI. In fact, the majority of PW appear not to be protected against IDD and its consequences. In future, a comprehensive study should be carried out to determine the levels of iodine in salt at the retail outlets, villages and households in Sarawak.

Background: A mandatory universal salt iodization (USI) has been implemented in Sarawak, Malaysia since 2008. Objectives: The aim of this study is to assess the current iodine status among school-aged children (SAC) and pregnant women (PW) after 10 years of USI implementation in Sarawak. Methods: This cross-sectional survey among school-aged children and pregnant women was conducted between July and October 2018 in Sarawak. The multistage proportionate to population size sampling technique was used to select 30 schools and 30 maternal and child health care clinics. A total of 1200 children aged 8 to 10 years and 750 first-trimester pregnant women were randomly selected to participate in the study. Iodine excretion level in urine was determined according to the World Health Organization classification. Results: A total of 988 children and 677 PW participated in the study with a response rate of 82.3% and 90.2%, respectively. The overall median urinary iodine concentration (UIC) level among the children was 126.0 μg/L (interquartile range [IQR], 71.0-200.9 μg/L) and classified as adequate iodine status. The median UIC among PW was 123.9 μg/L (IQR, 56.5-192.1μg/L) indicating inadequate iodine status. Conclusion: The present findings indicate that despite adequate iodine status in children, the majority of PW still showed inadequate iodine status. Thus, comprehensive monitoring of the iodine deficiency disorder problem among PW is warranted.