Statistical analysis
Data were analyzed using the Statistical Package for Social Sciences (SPSS) (IBM, Chicago, USA, version 16). Descriptive statistics were used to summarize the data, with categorical variables expressed as percentages and numbers and quantitative data presented as mean, median, standard deviation, range, and interquartile range. Statistical comparisons were performed using Student's t-test for comparing means, the Mann-Whitney U test for comparing mean ranks, and the Chi-square test (with Yates correction when applicable) for comparing proportions. The significance level was set at p≤0.05.