Statistical analysis

Logarithmic transformation was performed to achieve a normal distribution. Normally distributed data are presented as means ± SD and were compared using two‐way Student's t‐test or two‐way ANOVA followed by post‐hoc multiple comparisons using the Tukey–Kramer test. Non‐normally distributed data are expressed as medians, 25^th and 75^th percentiles, and minimum and maximum values excluding outliers, and were compared using the two‐way Mann–Whitney U test. The two paired groups were analyzed by Wilcoxon signed‐rank test. Scatter plot data are expressed as Spearman's correlation (r) and analyzed by Spearman's correlation test. A value of P < 0.05 was considered statistically significant.