Relationship between environmental selenium level in Kaschin-Beck areas and Kaschin-Beck disease happened in Xi＇an City

Abstract

Objective To measure the selenium concentration in external environment and to investigate its relationship with Kaschin-Beck disease（KBD） happened. Methods According to the distribution of KBD in Xi＇an, all residents lived in the 127 villages in KBD areas over the age of 7 were clinically examined. Forty samples of soil（500 g each, 15 cm below the earth surface）, wheat and corn（350 g each） were taken from each KBD area（county, district）. Five villages of Hu County（in non-KBD areas） were chosen as control group and fifty samples of soil, wheat and corn in non-KBD areas were collected. Selenium concentration was measured by atomic fluorescent spectrometer. Results A total of 98 561 persons were examined and 7 971 patients were found in Baqiao, Lantian, Zhouzhi and Lintong Counties （district）. The detective rate was 8.09%. The lowest detective rate was 4.48%（10/223） in Baqiao District and the highest was 9.66% （104/1 077） in Zhouzhi County. The medians of selenium concentrations of soil, wheat and corn in 4 KBD areas were 91.29, 7.75 and 16.63 μg/kg, respectively and in non-KBD areas were 146.84, 18.83 and 0.00 μg/kg, respectively. There were significant differences between KBD and non-KBD areas（Z = - 3.080, - 5.049, - 5.870, all P 〈 0.05）. The occurrence of KBD was associated with wheat and soil selenium level in KBD areas（r = - 0.93, - 0.40, all P 〈 0.05）. Conclusions The environmental selenium content is in lower level in Xi＇an City. Selenium deficiency in food intake contributes to the pathogenesis of KBD in Xi ＇an. Key words: Kaschin-Beck disease; Selenium ; Soil; Grains