Idiopathic scoliosis in Singapore schoolchildren - A prevalence study 15 years into the screening program

Study Design. A point prevalence survey of 72,699 schoolchildren in four age groups was performed. Objectives. To determine the prevalence rates of idiopathic scoliosis and to compare with a previous prevalence study done 15 years earlier. Summary of Background Data. Prevalence rates for idiopathic scoliosis of 5 degrees or more in schoolchildren were established in a study performed in 1982. There have been no previous data on prevalence rate changes over time. Methods. A total of 35,558 boys and 37,141 girls from randomly selected schools were screened for scoliosis. Those with scoliometer readings of more than 5 degrees underwent radiographic evaluation. Prevalence rates were calculated for scoliosis at a predefined Cobb angle of 10 degrees and 5 degrees, the latter for comparison with the previous prevalence study. Curve type and distribution, pubertal status, and symptoms were correlated with the prevalence data. Results. Prevalence rates were 0.05% for girls and 0.02% for boys at 6 to 7 years of age, 0.24% for girls and 0.15% for boys at 9 to 10 years of age, 1.37% for girls and 0.21% for boys at 11 to 12 years of age, and 2.22% and 0.66%, respectively, for girls and boys at 13 to 14 years of age. The ratio of girls to boys increased from 1.6 at 9 to 10 years of age to 6.4 at 11 to 12 years of age. Thoracolumbar curves were the most common (40.1%), followed by thoracic curves (33.3%), double/triple curves (18.7%), and lumbar curves (7.9%). Older children had greater proportions of larger curves. Compared with the previous prevalence study in 1982, there was a significant increase in the prevalence rate in girls 11 to 12 years of age. Screening of 11- to 12- and 13- to 14- year-old girls detected curves in the range suitable for bracing, with nearly 96% and 32% of the age groups, respectively, still amenarche or within a year of menarche, and 57% and 34% of the age groups, respectively, having low Risser grades of 0, 1, and 2. Conclusions. The overall prevalence rate of idiopathic scoliosis in our school population in 1997 was 0.93% in girls and 0.25% in boys. The prevalence rates were low at 6 to 7 and 9 to 10 years of age but increased rapidly to 1.37% and 2.22% for girls at 11 to 12 and 13 to 14 years of age, respectively. The prevalence rate increased significantly in 11- to 12-year-old girls over a 15-year period from 1982 to 1997. Screening of 11- to 12- and 13- to 14-year-old girls identified a significant number who could benefit from brace treatment.