Statistical analysis
The SPSS software (Armonk, New York corporation, USA) was used for data
analysis, and GraphPad Prism (version 6.0, San Diego, California, USA)
was used to plot graphs. All data are expressed as the mean ± SD. The
independent sample t-test was used to compare and analyse data between
the two groups, with homogenous variance of the bivariate normal
distribution. One-way analysis of variance was used to analyse the
differences between the two groups. Normally distributed bivariate data
were analysed using the Pearson correlation test, while non-normally
distributed bivariate data were analysed using the Spearman correlation
test. P values < 0.05 were considered statistically
significant.