Investigation Study for Mental Retardation Childen in Tianshui, Lanzhou and Yuzhong County

In order provide with basis data of recovery and education of M.R.Children in Gansu province,From March to May in 1997 and March,1999,We made a investigation to 16781 primary school students in Tianshui,Lanzhou and Yuzhong.And the illness rates of M.R.are 2.12‰,5.41‰,and 12.01‰.The number of M.R.Children that boys is 60.36%,and girls is 39.09%,the rate between girls and boys is 1 26:1.The rate of the boys is higher than that of the girls.The M.R.rate of the pupils from villages is 7.09‰ and 5.89‰ in cities.After statistics examination(u>2.58),P<0.01.The difference between the cities and the villages are significant.The rates of the villages are higher than the cities.The reason that the children suffer from.M.R.Inborn factors and before birth factors are 27.21%,factors at birth is 20.59%,factors after birth is 25%,unknown reason and culture lag are 20.59%.And the author gives the suggestion according to the conclusion of the study.