Statistical analysis
Statistical analysis was performed using the SPSS 16.0 (SPSS Inc., Chicago, IL) software. The Shapiro-Wilk test was used to test the normality of data distribution. The independent sample t-test was used for data with normal distribution; data shown as mean ± standard deviation in the table. Numerical data without normal distribution were analyzed using the Mann-Witney U test and shown as median (maximum-minimum) values. Categorical data were analyzed using the Chi-square and Fischer’s exact tests and shown as percentage (%). Statistical significance was assessed as p-values <0.05.