Data Synthesis
For continuous data, we used the inverse-variance method and the data
were pooled as mean difference (MD) using Review Manager Software
(version 5.3) for windows. For dichotomous data, we used the
Mantel-Hanszel method and the data were pooled as relative risk (RR)
using OpenMeta [Analyst] software for windows. We assessed the
heterogeneity by the Chi-square test and its extent was determined byI -square, such that values of p < 0.1 or
I2>50% were significant indicators of
heterogeneity. We used the random-effects model to analyze heterogeneous
data and fixed-effects model for the analysis of homogeneous data and
performed a sensitivity analysis to solve the heterogeneity whenever
detected.