Iodine deficiency disorders among pregnant women in Sarawak, Malaysia

Abstract

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.