Standardized evaluation of iodine nutrition in West Africa: the African phase of the thyromobil program.

Extensive programs of iodine supplementation by iodated salt have been implemented in Africa during the last decade. The present work evaluated their effectiveness in Benin, Burkina Faso, Mali, and Togo. A van equipped with a sonographic device visited 39 sites in the four countries. The prevalence of goiter was evaluated on the basis of the determination of thyroid volume by ultrasonography in 4,011 randomly selected 6- to 12-year-old schoolchildren of both sexes in the 39 sites. The concentration of urinary iodine was measured in 1,545 of these children. The iodine content of table salt collected at home by the children was measured by test kits in 3,202 salt samples, 415 of which were also analyzed by titration. Based on the results obtained by the kits, 83.7% to 97.9% of the salt samples contained iodine. However, the test kits had a low sensitivity and specificity in comparison with titration. The median urinary iodine was within an acceptable range (100-300 14 g/L) in the four countries, but almost one-third of the values were still below normal. The prevalence of goiter was normal (< 5%) in Benin and Togo, and it was 22.4% and 13.4%, respectively, in Burkina Faso and Mali. These results indicate marked improvement of the status of iodine nutrition in comparison with the situation reported only a few years ago in the same countries, but quality control of the iodine content of salt and monitoring of the iodine status of the populations need to be improved.