123 children with Kashin- Beck disease (KBD) and 84 normal children at the age of 2-13 in the KBD-affecter area have been continuously investigated for 4 years. It was found that 83% of KBD children had metaphyseal lesions and 66.9% of them had lesions in bone ends, and that the natural recovering rate of metaphyseal lesions from the 1st year to the 4th year was 22%, 43%, 57.8% and 73.6% respectively, and the natural recovely to the lesions of bone end was not found in all cases. It was also found that 25.2% of KBD children had an abnormal ratio of finger joint width and fingerwidth. Among them,2 changed from abnormal to normal and 17 from normal to abnormal. Only 2 children had an abnormal ratio of finger length and hand width. All the 84 normal children in the KBD-affected area had normal ratio of two ratios. No new case whose ratio turnd abnomal was found in 4 years. Our observations suggest that it is not reasonable to take the varying rate of metaphyseal lesions as the only evaluating criteria of cure and prevention of KBD because the natural recoveing rate of metaphyseal lesions is very high. It seems to be more reliable to combine the varying rate of metaphyseal leisions with the ratio of finger joint width and figer width as the evaluating criteria of cure and prevention of KBD.

This paper presented the relationship between age and Ⅹ—ray signs in metacarpophalanges of children's hands with Kashin—Beck disease. The result showed that Ⅹ—ray signs of metaphysis in metacarpophalanges of children were decreased with age ,but the types and the positive rate of Ⅹ—ray signs in the distal end of bones ,epiphyses and carpals were increased with age. The authors consider that articular lesions in Kashin—Beck disease will be more serious and enlarge with age.

The relationship of cause-result between low selenium (Se) and Kashin-Beck disease (KBD) was probed by the prospective study of epidemiological method with regarding low-Se as an exposure factor in this paper. 597 healthy children lived in KBD areas with low, middle and high prevalence were divided into the low-Se exposed group and the non-low-Se exposed group according to their Se content in hair. The low-Se exposed group was divided into three subgroups, such as Se content in hair≤110 ng/g, 110 ng/g＜Se content in hair≤150 ng/g and 150 ng/g＜Se content in hair≤200 ng/g, respectively. Six new cases of the total with KBD (incidence was 0.574% person-year) were found in the low-Se exposed group during three years period of the investigation. No new case was found in the non low-Se exposed group . KBD incidence was not significantly different between those two groups. Two new cases were found in children with Se content in hair kept below 110 ng/g during three years (incidence: 1.21% person-year). SMR in each group indicated that the new cases observed in the low-Se exposed group was remarkable lower than the new cases expected. It was not observed that the dose-response relationship between low-Se and KBD, and was not supported that the low-Se was a predominant factor to cause KBD.