Statistical analysis
All data were analyzed using the IBM Statistical Package for the Social
Sciences (SPSS) version 21.0 and MS-Excel 2010 software. The normality
distribution of scale variables was checked using the Kolmogorov-Smirnov
test. Data were expressed as median (interquartile range) or mean ±
standard deviation for those with non-parametric or parametric
distribution, respectively. The paired sample t-test or Wilcoxon test
was used for dependent samples, whichever is appropriate. Independent
samples were compared with the Mann-Whitney U test. Pearson’s chi-square
test was used for categorical variables. Scale data were compared with
Pearson’s or Spearman’s correlation tests according to their
distributions. Two-sided p-values less than 0.05 were considered
statistically significant.