GEOGRAPHICAL DIFFERENTIATION OF SELENIUM CONTENT IN HAIR FROM CHILDREN AND YOUNGSTERS IN CHINA——A discussion about relationshipbetween selenium deficiency and geographical epidemiology of the Keshan disease / 营养学报

ABSTRACT

Statistics shows that frequency distribution of selenium content in hair samples from children and youngsters in China is subject to a positive skewness, which is made up of three juxtaposed truncated normal frequency distribution. Its accumulative frequency distribution on a probability paper appears as a broken line with two broken points (110 and 520 ppb Se). Therefore, these two broken points might be used as classification indicatrix. Different selenium contents in hair samples are sorted out into three classes low (0ppb). A distribution map of selenium content in hair from children and youngsters in China has been plotted.As shown in the map, areas with low content of selenium in hair are fundamentally in accordance with epidemic areas of Keshan disease and Kaschin-Beck's disease of man. These two diseases are endemic in relation to selenium deficiency in the environment. A difference of mean content of selenium in hair between endemic areas and nonendemic areas is statistically very significant. Samples of hair with high content of selenium are found in the Northwestern part of China, big cities and areas occurring selenosis in livestock and man.Geographical differentiation of selenium content in grain is the main cause concerning the geographical differentiation of selenium contnet in the hair of men.