Statistical methods:
Statistical analysis was descriptive, exploratory, and generally limited
to frequency or summary statistics (e.g., means ± standard deviation or
medians ± quartiles). Demographic information was summarized according
to the type of data by descriptive statistics (n, mean, standard
deviation, median, the difference between percentiles) or frequency
distribution (n and %). The Student’s t-test was used for continuous
variables, the analysis of variance for categorical variables, and the
Pearson’s chi-square test for binominal variables. P values of
<0.05 were accepted as significant.