Prevalence of Adolescent Idiopathic Scoliosis among Female School Children in Singapore

Introduction: Screening for scoliosis started in Singapore schools in 1982 and is currently being done for both boys and girls, as part of the annual school-based health screening programme in all primary and secondary schools. The screening levels in the current protocol were based on the 1997 prevalence study by Wong et al. In the study, it appeared that there was a significant increase in prevalence rates between 9- and 11-year-old girls (i.e. between Primary 4 and Primary 6) but there was no data on the prevalence rates of scoliosis in 10-year-old girls (Primary 5) and in 12-year-old girls (Secondary 1). In order to decide on whether to make changes to the screening levels, a review was conducted to determine the prevalence of scoliosis among the 10-year-old girls (in Primary 5) and 12-year-old girls (in Secondary 1). Materials and Methods: A total of 93,626 female students, aged between 9 and 13 years old were screened. The study covered all of the 183 primary schools and only 83 of the 165 secondary schools due to a disruption of health screening in schools during the outbreak of SARS (severe acute respiratory syndrome). In mid-2003, schools in Singapore were closed because Singapore was one of the countries affected by SARS. Scoliosis screening was done for all female students in the Primary 4, 5 and 6 levels as well as in the Secondary 1 and 2 levels. Male students were routinely screened for scoliosis in the Primary 6 and Secondary 2 levels. Scoliosis screening was done by measuring the angle of trunk rotation (ATR) using a scoliometer. All students with ATR >= 5 degrees were referred to the Student Health Centre (SHC) where second-tier screening was done. At SHC, if ATR >= 5 degrees, postero-anterior radiograph of the spine was done. Of the 3186 female students in the primary level, aged between 9 and 13 years old who were referred to SHC for the second-tier screening, 2438 attended, and for secondary students aged between 12 and 13 years old, 1587 out of 1720 students attended. Results: The prevalence rates of idiopathic adolescent scoliosis for the 9- to 13-year-old female students were 0.27%, 0.64%, 1.58%, 2.22% and 2.49%, respectively, which showed an increasing trend in the prevalence rates with increasing age. There was a significant increase in the prevalence rates of adolescent idiopathic scoliosis (AIS) in the 10- to 11-year-old females compared to the 9-year-old females (OR, 1.7; 95% CI, 1.1-2.4; P = 0.010). There was also a significant increase in the prevalence rates in the 12- to 13-year-old females (OR, 2.2; 95% CI, 1.4-3.3; P = 0.001). Conclusions: The study showed a significant increase in the prevalence rates of scoliosis in the 10- to 11-year-old female students and again a significant increase in the prevalence rates in the 12- to 13-year-old female students. Since the prevalence rate for the 9-year-old females was quite low (0.27%), and there was a significant increase in the prevalence rates in the 10- to 11-year-old and 12- to 13-year-old females, it was recommended that screening for females be performed every year commencing at 10 years old (Primary 5) until 13 years old (Secondary 2).