Application of the electronic scoliometer in school-based scoliosis screening among elementary school students and analysis of factors associated with suspected scoliosis

Background Scoliosis imposes a growing health burden on school-age children in China, yet data specific to elementary school students aged 6–12 years remain scarce. This study aimed to compare the positive screening rate and screening efficiency of the electronic scoliometer (E-scoliometer) with those of the manual scoliometer (M-scoliometer), and to identify modifiable risk factors for suspected scoliosis in this younger age group. Methods A school-based cross-sectional study was conducted among 11,587 students in grades 1–5 from 10 public elementary schools in Harbin, China (September 2024–May 2025), using multistage stratified cluster sampling. Classes were randomly allocated to the M-scoliometer group ( n = 5,697 pupils) or the E-scoliometer group ( n = 5,890). A stratified subsample of 3,600 students underwent posture assessment and parent-reported questionnaire survey. Associations were examined within two domains by binary logistic regression and then in a single joint generalized estimating equation (GEE) model providing mutual adjustment across domains and accounting for clustering of pupils within classes. Results The overall positive screening rate was 1.61%, increasing significantly from Grade 1 (0.26%) to Grade 5 (2.89%; p < 0.001). The two devices yielded comparable positive screening rates (M-scoliometer 1.67% vs. E-scoliometer 1.56%; difference 0.11 percentage points, 95% CI − 0.36 to 0.57; p = 0.706), while the E-scoliometer reduced mean screening time by 54.2% (16.04 s vs. 35.00 s; p < 0.001). In the joint GEE model (59 events, 9 parameters, 6.56 events per variable, optimism-corrected AUC 0.910), flat back (OR = 7.36), picky eating (OR = 4.19), daily physical exercise < 1 h/day (OR = 3.86), mild wasting (OR = 3.80), shoulder height asymmetry (OR = 3.06) and higher grade (OR = 1.43 per grade) were associated with higher odds of suspected scoliosis, whereas regular adjustment of chair and desk height (OR = 0.18) and regular rotation of classroom seating (OR = 0.19) were associated with lower odds. The association with thumb-inward grip pen-holding posture did not persist under mutual adjustment (OR = 1.55, 95% CI 0.77–3.11) and is reported as hypothesis-generating. Conclusion The E-scoliometer yielded a positive screening rate comparable to that of the M-scoliometer with markedly superior efficiency, supporting its adoption in large-scale school-based programs. The factors identified were largely modifiable, suggesting that promoting daily physical activity, improving nutritional behaviors, and standardizing classroom furniture management and seating rotation merit consideration in school-based scoliosis prevention strategies for elementary school children.