The association between physical activity and adolescent idiopathic scoliosis: improper sitting posture as a mediator

Background The association between physical activity (PA) and adolescent idiopathic scoliosis (AIS) remains unclear. This study investigates whether improper sitting posture mediates the relationship between PA and AIS in cross-sectional analyses. Methods This study utilized data on adolescents collected across 9 provinces in China in 2021, involving 3,536 participants for cross-sectional analysis. A multivariate logistic regression model was used to evaluate the associations among PA, improper sitting posture, and AIS. Mediation analyses assessed the mediating role of improper sitting posture in the association between PA and AIS. Subgroup analyses were performed to assess heterogeneity across groups. Results In the cross-sectional analysis, PA (OR = 0.985, 95%CI: 0.981–0.990, P < 0.001) was negatively associated with AIS, and improper sitting posture (OR = 1.989, 95%CI: 1.664–2.376, P < 0.001) was positively associated with AIS. Improper sitting posture partially mediated this relationship, with a mediation effect of −0.0011 (95% CI: −0.0018 to −0.0005), representing 7.10% of the overall effect variability. Conclusion PA was negatively associated with improper sitting posture and AIS, and improper sitting posture was positively associated with AIS. Improper sitting posture partially mediated the association between PA and AIS. These results suggest that PA and the avoidance of improper sitting posture may help prevent AIS.