A 5-year epidemiological study on the prevalence rate of idiopathic scoliosis in Tokyo: school screening of more than 250,000 children.

Background: School screening for scoliosis is a powerful tool that can be used to identify children who may have scoliosis. There have been no reports on the recent prevalence of idiopathic scoliosis in Japan since 1988.

Methods: A 5-year epidemiologic study was performed to determined the prevalence of idiopathic scoliosis, the curve magnitude, the distribution of this magnitude, and the sex ratio in school children. Between 2003 and 2007, a total of 255,875 children aged 11-14 years were screened.

Results: A total of 3,424 children were found to be positive as a result of Moiré topography. With radiographic examination, 2,225 (65.0%) children with a Cobb angle of 10° or more were detected. The overall prevalence rate in schoolchildren 11-14 years of age with Cobb angles of 10° or more was 0.87%. The prevalence rate in girls increased from 0.78% at the age of 11-12 years to 2.51% at the age of 13-14 years. For boys, the prevalence rates were 0.04% at the age of 11-12 years and 0.25% at the age of 13-14 years. The overall ratio of girls to boys with scoliosis was 11:1. The ratio of girls to boys was 17:1 at the age of 11-12 years and 10:1 at the age of 13-14 years.

Conclusions: The majority of the curves fell in the range of 10°-19°. There was a slight increase in the prevalence rates of children with a curve of high magnitude (≥20°) as compared to the prevalence rate in 1988. We suggest that school screening for scoliosis is effective for early detection; however, it is first necessary to review and optimize the target groups.