Statistical analysis
The data were analyzed using SPSS 22.0 statistical software, and the count data were described by rate or composition ratio. Normally‐distributed measurement data are described by the mean ± standard deviation, and data with a skewed distribution are expressed by M (range). Comparisons between groups of count data were made using the test or Fisher's exact probability method. Comparisons between groups of measurement data conforming to a normal distribution were made using a 