School screening for scoliosis by the Chiba University Medical School screening program. Results of 1.24 million students over an 8-year period.

The screening program for scoliosis started by Chiba University in 1979 consists of using moiré topography, low-dose roentgenography and a final ordinary x-ray examination. The number of children screened through this Chiba University Medical School (CUMS) screening program to 1986 amounted to 1,246,798. The incidence of scoliosis of more than 15 degrees increased linearly according to age from the fifth grade primary school children (0.07% in boys, 0.44% in girls) to the second grade junior high school students (0.25% in boys, 1.77% in girls). The female predominance of scoliosis cases with curvatures of more than 20 degrees detected during the total period was 10:1 and this female predominance was the same for primary school children and junior high school students. According to a study of the incidence of scoliosis by districts, (areas were divided according to population density and urbanization) there were no significant differences in the fifth grade primary school children between the sparsely and densely populated areas. In the cases of children beyond the fifth grade primary school level, however, the incidence in the densely populated areas were significantly higher than those in the sparsely populated districts. The incidence of scoliosis of more than 20 degrees decreased significantly every year among junior high school students, because they were screened periodically in school and the scoliotic students who had already been detected were left out of the next screening. This study establishes that screening for scoliosis by the CUMS screening program is cost-effective with a low risk of radiation hazards.