Meta-analysis
Heterogeneity was assessed using the I2 index, with I2 > 50% indicating significant heterogeneity21. Continuous variables of interest were described with means, standard deviations, and sample size to estimate confidence intervals (CIs). Dichotomous variables were described using numerators and denominators to estimate proportions and CIs. The random effects model was used to estimate summary statistics for variables of interest, where individual studies were treated as a random variable. To estimate the difference in variables of interest over time, only publications that contained both baseline and follow-up means and standard deviations were used. We calculated risk ratios using the Mantel-Haenszel method and the mean difference with inverse variance. All statistical analyses were performed using Review Manager 5.3 software (Cochrane).