Statistical analysis
The results were analysed with IBM SPSS statistics version 23 for
Windows (IBM Corp, Armonk, NY, USA). The age variable was divided into
the following three groups: ≤ 30 years old, 31 to 49 years, and ≥ 50
years. The Kolmogorov-Smirnov test was used to assess the normality of
the distribution of the continuous variables. The mean±standard
deviation or median (interquartile range) was used to summarize the
results of the continuous data. The categorical variables are presented
as percentages and counts. An independent t-test or a Mann-Whitney U
test was used for the between-group comparisons of the continuous data,
and a chi-square test was used to compare the differences in the
categorical data. P < .05 was considered indicative of a
significant difference.