Causal relationships of physical activity and leisure sedentary behaviors with scoliosis: A two-sample Mendelian randomization study

Scoliosis is the most common spinal deformity in children and adolescents, and modifiable lifestyle factors such as sedentary behavior and physical activity (PA) have been suggested to influence its risk, although evidence remains conflicting. This study aimed to investigate the relationships between leisure sedentary behaviors, PA, and the risk of scoliosis by using two-sample Mendelian randomization (MR). Genetic variation in television watching time, mobile phone use time, moderate-to-high intensity physical activity (MVPA), and vigorous physical activity (VPA) were used as IVs. The outcome data were derived from the Finn-Gen Scoliosis dataset. The causal relationships were estimated with inverse variance weighted (IVW), MR-Egger, and weighted median methods. Sensitivity analysis was conducted using Cochran Q test, MR-Egger intercept test, Mendelian Randomization Pleiotropy Residual Sum and Outlier (MR-PRESSO), leave-one-out analysis, and funnel plot to estimate the robustness of our findings. The IVW results indicated the following: watching TV time (odds ration [OR] = 0.623, 95% confidence interval [CI]: 0.21-1.78, P = .38); time spent on mobile phones (OR = 0.57, 95% CI: 0.16-1.96, P = .37); MVPA (OR = 0.53, 95% CI: 0.09-3.15, P = .49); VPA (OR = 0.62, 95% CI: 0.21-1.78, P = .61). The primary IVW MR analysis results were consistent with those of the multiple sensitivity MR Analysis. Genetic susceptibility to leisure sedentary behavior and PA are not associated with the risk of scoliosis. The observed associations may be the result of shared genetic effects or environmental confounding factors.