Stable Iodine Nutrition During Two Decades of Continuous Universal Salt Iodisation in Sri Lanka.

Renuka Jayatissa,Jonathan Gorstein,Lakdasa D Premawardhana,Onyebuchi E Okosieme,John H Lazarus

doi:10.3390/nu12041109

Renuka Jayatissa, Jonathan Gorstein + Show 3 more

Open Access

https://doi.org/10.3390/nu12041109

Copy DOI

Abstract

Universal salt iodisation (USI) was introduced in Sri Lanka in 1995. Since then, four national iodine surveys have assessed the iodine nutrition status of the population. We retrospectively reviewed median urine iodine concentration (mUIC) and goitre prevalence in 16,910 schoolchildren (6–12 years) in all nine provinces of Sri Lanka, the mUIC of pregnant women, drinking-water iodine level, and the percentage of households consuming adequately (15 mg/kg) iodised salt (household salt iodine, HHIS). The mUIC of schoolchildren increased from 145.3 µg/L (interquartile range (IQR) = 84.6–240.4) in 2000 to 232.5 µg/L (IQR = 159.3–315.8) in 2016, but stayed within recommended levels. Some regional variability in mUIC was observed (178.8 and 297.3 µg/L in 2016). There was positive association between mUIC in schoolchildren and water iodine concentration. Goitre prevalence to palpation was a significantly reduced from 18.6% to 2.1% (p < 0.05). In pregnant women, median UIC increased in each trimester (102.3 (61.7–147.1); 217.5 (115.6–313.0); 273.1 (228.9–337.6) µg/L (p = 0.000)). We conclude that the introduction and maintenance of a continuous and consistent USI programme has been a success in Sri Lanka. In order to sustain the programme, it is important to retain monitoring of iodine status while tracking salt-consumption patterns to adjust the recommended iodine content of edible salt.

Highlights

Iodine is a micronutrient that primarily acts through the thyroid gland and its two hormones, and it is vital to the integrity of many physiological functions in the human body [1,2]
We conclude that the introduction and maintenance of a continuous and consistent Universal salt iodisation (USI) programme has been a success in Sri Lanka
We demonstrated in this retrospective review of data from four national iodine surveys of over more than two decades of continuous salt iodisation that (i) median urine iodine concentration (mUIC) has consistently been in the adequate range with a sequential increase within safe and recommended limits; (ii) the goitre-prevalence rate to palpation in children between 6–12 years significantly decreased between 2000 and 2016 (18.0% to 1.9%; p = 0.000); and (iii) the percentage of adequately iodised household salt samples significantly increased during this period

Summary

Introduction

Iodine is a micronutrient that primarily acts through the thyroid gland and its two hormones (thyroxine and triiodothyronine), and it is vital to the integrity of many physiological functions in the human body [1,2]. Iodine deficiency may affect multiple aspects of human development (including intrauterine physical and neurological development), linear growth, and physiological organ function. Organs such as the brain and nervous system are vulnerable in their formative stages during intrauterine life [1,2]. Iodine deficiency is relatively easy and inexpensive to prevent through universal iodisation of all edible salt. This is a pure food-chain effect, beginning with soil erosion and leading to environmental iodine deficiency, and a lack of iodine sources in our typical diet.

Methods

Findings

Discussion

Conclusion