Statistical Analysis
Continuous variables are expressed as the mean ± SD and categorical
variables were reported as counts and frequencies. Intergroup
differences were compared by using analysis of variance or the
Kruskal-Wallis test for overall comparisons and the T-test or
Mann-Whitney U test for two-group comparisons. Statistical analyses were
performed with SPSS statistical software version 11.0 (Cary, North
Carolina). All statistical tests were 2 sided, and a p value <
0.05 was considered significant.