Trace Element Levels in Scalp Hair of School Children in Shigatse, Tibet, an Endemic Area for Kaschin-Beck Disease (KBD).

Kaschin-Beck disease (KBD) is an endemic osteoarthritis, and the etiology is closely related with levels of trace elements in the human body. Currently, it is clear that the selenium (Se) status of children in KBD areas is lower than that in non-KBD areas in the Tibetan Plateau, whereas role of other elements are yet unknown. This study aimed to assess some essential trace elements (Se, Mo, Mn, Zn, Fe, Cu, Co, and Sr) in children using scalp hair as a biomarker, and 157 samples from school children aged 8-14 years old were collected from both KBD and non-KBD areas in Shigatse, Tibet. Se and Mo were measured by inductive coupled plasma mass spectrometry, and the other elements were determined by inductive coupled plasma optical emission spectrometry. Compared with the non-KBD areas, Se, Mo, Mn, Fe, Zn, Co, and Sr levels of children in KBD areas were found to be significantly different (P < 0.05); while in linear discriminant analysis, only Se and Zn were found to contribute to the KBD prevalence in the study area. The hair Se level of children in KBD areas ranged from 0.115 to 0.299 mg/kg, while in non-KBD areas it ranged from 0.135 to 0.519 mg/kg. The Zn content of children's hair was between 83 and 207 mg/kg in KBD areas, while it was 37 and 219 mg/kg in non-KBD areas. Lower Se and higher Zn levels in children in KBD areas was found when compared with non-KBD groups. In addition, Mo levels were found to be different between KBD areas and non-KBD areas on the opposite side of the Yarlung Zangbo River, but no close relationship was shown because there was no difference compared with the non-KBD area on the same side of the river. Our observations suggest that Se deficiency is still an important factor for the occurrence and prevalence of KBD, while the relationship between Zn and KBD needs to be further explored in the Tibetan Plateau.