Effects of mandatory iodization on the iodine content of retailer and household salt in South Africa.

Voluntary iodization of table salt prior to 1995 had a beneficial effect on the prevalence of goitre in some areas in South Africa. However, it was, due to limited availability and unequal access, unsuccessful in eradicating iodine deficiency and endemic goitre. Against this background the international focus on the eradication of IDD stimulated the introduction of mandatory iodization of table salt in South Africa at the end of 1995 at a higher iodine concentration than before. Within one year the availability of iodized salt at the retail level increased considerably and the iodine content of iodized salt more than doubled from 14 to 33 ppm, accompanied by considerable variation in the iodine concentration. In a national study more than 2 years after the introduction of mandatory iodization the mean iodine concentration of household salt was 27 ppm and the median 30 ppm, and 62.4% of households used adequately iodized salt. These improvements, both at the retail and household level, in the iodine content and coverage of iodized salt after the introduction of mandatory iodization could be further enhanced by eliminating the factors responsible for the use of inadequately iodized salt, with a particular focus on low socio-economic households.