School of Economics
31 Buccleuch Place
Institutional Affiliation: The University of Edinburgh
NBER Working Papers and Publications
|July 2013||The Cognitive Effects of Micronutrient Deficiency: Evidence from Salt Iodization in the United States|
with James Feyrer, David N. Weil: w19233
Iodine deficiency is the leading cause of preventable mental retardation in the world today. The condition, which was common in the developed world until the introduction of iodized salt in the 1920s, is connected to low iodine levels in the soil and water. We examine the impact of salt iodization on cognitive outcomes in the US by taking advantage of this natural geographic variation. Salt was iodized over a very short period of time beginning in 1924. We use military data collected during WWI and WWII to compare outcomes of cohorts born before and after iodization, in localities that were naturally poor and rich in iodine. We find that for the one quarter of the population most deficient in iodine this intervention raised IQ by approximately one standard deviation. Our results can expla...
Published: James Feyrer & Dimitra Politi & David N. Weil, 2017. "The Cognitive Effects of Micronutrient Deficiency: Evidence from Salt Iodization in the United States," Journal of the European Economic Association, vol 15(2), pages 355-387. citation courtesy of