Recently in Japan there has been a great interest in the increasing number of fractures in children. However because of the lack of scientific data in the past, a clear analysis was difficult to make.
　In this study we attempted to evaluate the incidence of fractures in children in Niigata city, and the possible factors of this increase.
　The first survey was done to all students in third grade of junior high school about their past history of fractures by a questionaire in 1981 and another one in 1990. The incidence of the children's fracture was 12.6% (in boys 16.7%, in girls 8.5%) in 1981: on the other hand in 1990 the incidence increased to 15.5% (in boys 20.1%, in girls 10.8%). Among girls, there was no significant increase in the number of fracture in all grades, however in boys the number increased after fifth grade of elementary school. From the list of injuries which was reported by school nurses after the organized system by the Japanese Ministry of Education the number of fractures in each year were collected from 1975 to 1989.
　The number and the incidence of fractures to all students had been increasing every year, the incidence of fractures for every 100 students in 1975 was 0.68, and this increased to 1.19 in 1989. To evaluate the possible causes of this increase an analysis of the background of the students who were listed in the report was done in 1981 and 1990 by a questionaire. As a control group, students whose student number is just before and after the involved subject were also studied. The X-rays of the subjects were evaluated by visiting the hospitals where diagnosis had been made.
　The background such as eating habits and nutrition, body-height and weight, fitness and sports ability, and the mechanism of injury were compaired between the two groups, one is the fracture group whoes fracture are comfirmed by this study and the control group who has no history of suffering fractures. The sports ability of the fracture group tends to better, their average body-height and weight tends to be taller and heavier than those of control group.
　It can be summarized that the incidence of fractures in students seemed to be increasing and level of sports activity is one of the main factor for this tendency.

DESCENTE SPORTS SCIENCE Vol.13/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE