Data analysis
The meta-analysis was performed using RevMan version 5.3 software[25]. For continuous variables, data were synthesized using the mean difference (MD) with a 95% confidence interval (CI) or standardized mean difference (SMD). An odds ratio (OR) or risk ratio (RR) was used to analyze discontinuous variables. The Chi-squared test and I -squared (I2 ) tests were used to assess for statistical heterogeneity. High heterogeneity in the results was identified if the tests were statistically significant (p < 0.05) and the I 2 > 50%, in which case a random-effects model was selected. Otherwise, a fixed-effects model was used. Sensitivity analysis was conducted by removing individual studies or eliminating studies with a high risk of bias. If necessary, a subgroup analysis was conducted according to the different intervention conditions (dose, duration, and population)[26].