Adequacy assessment of a universal salt iodization program two decades after its implementation: A national cross-sectional study of iodine status among school-age children in Tunisia

Abstract

In the framework of a worldwide policy to eliminate iodine deficiency (ID) disorders, universal salt iodization was adopted in Tunisia two decades ago. The present study aims to evaluate this strategy, using both performance and impact indicators. A total of 1560 children, aged 6-12 years, were randomly sampled using a national, two-stage, stratified, cross-sectional cluster survey in 2012. Urinary iodine concentration (UIC) of the subjects, and household salt iodine content, were analyzed. The national median UIC was 220 μg/L (95% confidence interval (CI): 199-241), indicating an acceptable iodine status at the population level. Only 11.4% (95% CI: 8.6-14.9) of the children had UIC <100 μg/L, but with large regional disparities (4.3% to 25.5%, p < 0.01), however, more than a quarter of the subjects were at risk of adverse health consequences due to iodine excess. Children from households of low socio-economic levels were more prone to inadequate UIC. The national median iodine concentration of household salt was 22 mg/kg (95% CI: 21-23). Only half of the households used adequately iodized salt (15-25 ppm), with large regional disparities. National ID rates are now well below the target criteria of WHO (World Health Organization) certification (<20% of children with UIC <50 μg/L and <50% with UIC <100 μg/L). The coverage of adequately iodized salt fell short in meeting the goals of USI (Universal Salt Iodization), i.e., >90% of households. Regular monitoring of iodized salt production lines must be strengthened with involvement by producers.