Selenium content in hair samples of people in Kaschin-Beck disease areas in Shaanxi Province / 中华地方病学杂志

ABSTRACT

Objective To compare selenium content in hair samples of people in Kaschin-Beck disease (KBD) areas and control areas in Shaanxi Province two years after stopping the selenium salt prevention,and to provide a scientific basis for development of targeted prevention measures and for decision-making.Methods In July 2014,the four KBD counties of Yongshou,Yuyang,Linyou and Nanzheng were selected as survey counties,meanwhile,four non KBD counties of Wugong,Mizhi,Qishan and Chenggu were selected as rural control groups and Lianhu District in Xi'an City was selected as a urban settlement control county.Four villages (communities) were selected as monitoring sites according to four directions as east,west,south and north in each county.In each monitoring site,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 hair selenium.Samples were prepared by wet digestion method,the content of selenium was determined by 2,3-diaminonaphthalene fluorescence method.Results A total of 576 hair samples were collected.The average hair selenium in each monitoring site was more than 0.20 mg/kg.Hair selenium was compared in KBD areas,rural non KBD areas,and urban non KBD areas,the differences were not statistically significant [(0.35 ± 0.18),(0.41 ± 0.28),(0.46 ± 0.19) mg/kg,F =1.544,P ＞ 0.05].In KBD areas and non KBD areas,there were 45 and 45 people with selenium content ＜ 0.20 mg/kg,accounting for 17.58％ and 14.06％;47 and 25 people with selenium content 0.20-＜ 0.25 mg/kg,accounting for 18.36％ and 7.81％;113 and 159 people with 0.25-＜ 0.50 mg/kg,accounting for 44.14％ and 49.69％;51 and 91 people with ≥0.50 mg/kg,accounting for 19.92％ and 28.44％.Hair selenium content of children aged 7-12 and adults was compared in KBD areas,rural non KBD areas,and urban non KBD areas [children(0.43 ± 0.35),(0.38 ± 0.19),(0.50 ± 0.16) mg/kg;adults(0.32 ± 0.17),(0.38 ± 0.19),(0.42 ± 0.21) mg/kg],the differences were not statistically significant (F =2.131,1.789,P ＞ 0.05).Hair selenium content was compared in different gender in KBD areas,rural non KBD areas,and urban non KBD areas [male(0.35 ± 0.18),(0.44 ± 0.33),(0.52 ± 0.15) mg/kg;female(0.35 ± 0.19),(0.38 ± 0.22),(0.41 ± 0.21) mg/kg],the differences were not statistically significant (F=1.598,1.790,P ＞ 0.05).Conclusion Two years after stopping the selenium salt prevention in Shaanxi Province,the selenium of population in Kashin-Beck disease areas in Shaanxi Province exceeds the human health threshold (0.20 mg/kg),and most people are in the medium or high levels of selenium,and are close to the levels of selenium in non-endemic areas.