Changes of selenium content in hair samples of people in Kaschin-Beck disease areas two months after stopping selenium salt in Shaanxi Province in 2012

Abstract

Objective To compare selenium content in hair samples of people in Kaschin-Beck disease (KBD) areas and non KBD areas two months after stopping selenium salt in Shaanxi Province, to provide a scientific basis for KBD control and prevention. Methods In September 2012, four historical KBD areas were selected, including Yongshou, Yuyang, Linyou and Nanzheng, four villages were selected as monitoring sites according to the four directions as east, west, south and north in each county. Meanwhile, four non KBD areas were selected, including Wugong, Mizhi, Qishan and Chenggu, which adjacent to the survey counties and were similar to the survey counties in environment and production and living conditions. Four villages were selected as monitoring sites according to the four directions as east, west, south and north in each county. Lianhu District in Xi'an city was selected as a urban non KBD area. Four communities were selected in the east, west, south and north as the monitoring sites. In each monitoring point, hair samples of 8 children aged 7-12 years old (gender balanced) and 8 adults over the age of 16 (gender balanced) were selected to determine the hair selenium. Samples were disposed by wet digestion method, the selenium content was determined by 2,3-diaminonaphthalene fluorescence method. Results A total of 256 hair samples were collected in the four KBD counties, 256 hair samples in four non KBD counties, 64 hair samples in one urban district. The average of hair selenium in each monitoring point was ≥0.25 mg/kg. Compared the hair selenium content in KBD areas, rural non KBD areas, and urban non KBD areas [(0.40 ± 0.23), (0.42 ± 0.28), (0.37 ± 0.38) mg/kg], the differences were not statistically significant (F= 0.045, P > 0.05). In KBD areas, the hair selenium content of 37 people was 0.05). Compared the hair selenium content in different gender in KBD areas, rural non KBD areas, and urban non KBD areas [maile: (0.43 ± 0.23), (0.43 ± 0.26), (0.40 ± 0.51) mg/kg; female: (0.38 ± 0.22), (0.41 ± 0.31), (0.34 ± 0.18) mg/kg], the differences were not statistically significant (F= 0.872, 3.589, all P > 0.05). Conclusion Two months after stopping to supply selenium salt in 2012 in Shaanxi Province, the hair selenium content of residents in KBD areas has not dropped significantly. Since this survey is carried out only 2 months after taking the measure, it is necessary to continue to monitor the selenium level in KBD areas. Key words: Kashin-Beck disease; Hair; Selenium; Surveillance