Because most environmental iodine is found in and around seawater, populations located in remote, mountainous regions are at greatest risk for iodine deficiency. Other groups at risk of iodine deficiency include women during pregnancy and postpartum period due to the increased iodine requirements associated with fetal development and breastfeeding, infants born to pregnant women deficient in iodine, and individuals who consume a vegan diet or use sea salt rather than iodized salt.