Environmental iodine deficiency and its relationship with Kashin-Beck disease (KBD) in some areas of Tibet

Kashin-Beck disease (KBD), as a severe endemic disease prevalent mainly in northern China, southeastern Siberia and North Korea, was also discovered in Tibet of China during the past three decades. In this study, 20 drinking water samples, 18 cropped soil samples, and 15 highland barley samples were collected in Sangri, Nimu, and Gongbujiangda County of Tibet to reveal the relationship between KBD occurrence and environmental iodine deficiency. According to our measurements, the iodine concentrations of environmental media samples (including drinking water, cropped soil and highland barley samples) from KBD-affected villages of Sangri, Nimu, and Gongbujiangda were generally lower than those from non-KBD villages of the corresponding county, indicating that the iodine deficiency in environment plays an important role for the occurrence of KBD. Furthermore, in the KBD-affected villages of Sangri and Nimu, the highland barley samples have much lower iodine concentrations as compared with those from the corresponding non-KBD villages, whereas the differences of iodine concentration in drinking water sample between KBD-affected and non-KBD villages are relatively smaller, which means that food acts as a more important intake source of iodine than drinking water, and correspondingly, iodine deficiency in food contributes more to the KBD prevalence in the study area.