Longevity and selenium deficiency: evidence from the People's Republic of China.

Data were abstracted from the Atlas of Aged Population in the People's Republic of China and from The Atlas of Endemic Diseases and their Environments in the People's Republic of China. The spatial distribution of the elderly, those aged 80 years or more in 1982, in 2408 counties, was then compared with the prevalences of Kaschin-Beck and Keshan diseases, both of which involve extreme selenium deficiency. Pearson chi-square, the Mantel-Haenszel test for linear, association and Spearman correlation all clearly indicate that the elderly in China are not normally distributed. Far fewer people of advanced age reside in those counties in which Kaschin-Beck and Keshan diseases are endemic than in unaffected counties. The possible reasons for this are thought to include elevated mortality from endemic and chronic diseases in selenium deficient areas and accelerated ageing due to excessive cellular damage caused by free radicals. These two phenomena may be related.