[Influence of age and sex on threshold dose of mercury in Minamata disease as determined by hair mercury concentration].

The influence of age and sex on the threshold dose of mercury in Minamata disease was studied by dose-response analysis based on mercury concentrations in hair obtained mainly from adults living near the Agano River at the beginning of Niigata Minamata disease outbreak in 1965. The subjects were 174 male and 694 female inhabitants of polluted areas including 55 males and 66 females officially recognized as Minamata disease patients. Because of the large sex differences in numbers and age distributions, the data were analyzed separately for males and females. While revealing no sex difference in the threshold dose, hockey-stick regression analysis indicated an effect of age on threshold dose in females. Logistic regression analysis showed no interaction between age and hair mercury concentration. These results suggest that, in adults, neither sex nor age exert a considerable effect on the threshold dose of mercury in Minamata disease.