Factors Associated with Suspected Scoliosis Identified Through School Screening: The Role of Body Mass Index and Sports Participation

Background/Objectives: Adolescent idiopathic scoliosis (AIS) is a multifactorial condition with an unclear etiology. Previous studies have reported associations of scoliosis with female sex, lower body mass index (BMI), and lower physical activity levels. This study examined factors associated with suspected scoliosis identified through school screening, with emphasis on BMI and sports participation. Methods: A cross-sectional study was conducted during the 2019/2020 school year and included 18,216 adolescents. Suspected scoliosis was identified using the forward bend test (FBT). Logistic regression analysis assessed associations between suspected scoliosis and sex, grade, BMI, participation in the seven most frequently reported sports, and training frequency. Results: Higher BMI (odds ratio (OR) = 0.91, p < 0.001), participation in soccer (OR = 0.64, p < 0.001), gymnastics (OR = 0.58, p = 0.05), martial arts (OR = 0.66, p = 0.02), and higher recreational training frequency (OR = 0.92, p < 0.001) were associated with lower odds of suspected scoliosis. Female sex (OR = 2.49, p < 0.001) and higher grade level (6th: OR = 1.54; 8th: OR = 2.98; p < 0.001) were associated with increased odds of suspected scoliosis. Conclusions: Suspected scoliosis identified through school screening was more frequently observed among females and adolescents with lower BMI. Participation in certain sports and greater recreational physical activity were associated with lower prevalence and odds of suspected scoliosis. These findings reflect screening-based associations and do not imply causal relationships. The results support the importance of school-based screening and consideration of body composition and physical activity patterns in the early identification of adolescents with suspected scoliosis.