Almost one hundred years ago, the US instituted a salt iodine fortification program in order to rectify a goiter endemic throughout the country. The plan worked. Since then, one-by-one, countries around the world have been fortifying foods with iodine.
It was only 15 years ago when China instituted a fortification program. Recently, researchers in China conducted a study as a check-in to be sure the program was working as planned. They tested 4 different populations (each with different iodine requirements) from different regions of the country: children, pregnant women, lactating women, and adults. The goal was to evaluate any possible changes