Geologic implications in the distribution of endemic goiter in Colombia, South America

A survey of 37 communities supplied by stream water and receiving iodised salt for the last 10-20 years indicates that the presence of sedimentary rocks in the watersheds of streams more closely correlates with goiter prevalence than 12 other possible causative variables. These results support the hypothesis that sedimentary rocks rich in organic matter are the main source of water-borne goitrogens.