Evaluation of Salt Iodization at Consumption Level in North-Eastern Thailand

Abstract

Objectives: Iodine deficiency disorder (IDD) is an important health problem in Thailand, especially in northern and north-eastern regions. Since the introduction of iodized salt in 1960s many control programs have been implemented judging the effectiveness at community level. Concerns have been expressed regarding public health information and quality control of manufactured iodine-fortified salt (mandatory: 20- 40 ppm). This study assessed the iodine content in Thai table salts. Methods: Salt samples (n=438) from endemic areas in north-eastern Thailand including eleven districts from three different provinces were collected either by asking school children to bring salt used for home cooking or with the help of local health volunteers during home visits. Salt analysis was conducted by using a portable photometer for quantitative iodine determination (iCheckTM- iExTM IODINE). Results: Median iodine concentration was 7.0 ppm (IQR 0.0-32.9) being highest in district 2 and district 6 (51.9 ppm, IQR 24.4-82.7 and 36.6 ppm, IQR 32.0-49.1, respectively). Samples from province A (5.4 ppm, IQR 0.0-31.2) contained significantly less iodine than from province B and province C (20.6 ppm, IQR 5.7-34.4 and 26.3 ppm, IQR 5.9-34.7, respectively; p<0.001). 137 salt samples (31.3%) were not fortified, 24.4% were fortified at levels < 20 ppm and 30.1% were sufficiently fortified (20- 40 ppm); 14.2% were fortified above 40 ppm. Conclusions: Analysis revealed high variability in iodine content between and within different provinces. The results show that IDD programs need to address quality control at factory, retail and household levels.