Statistical analysis

Statistical analyses were performed using SPSS software version 17.0 for Windows (SPSS Inc., Chicago, Illinois, USA). Visual (histograms, probability plots) and analytical methods (Kolmogorov-Smirnov/Shapiro-Wilk test) were used to determine the normal distribution of the variables. Descriptive analyses are presented as means and standard deviations. The categorical variables are expressed as numbers and percentages. Numerical variables were compared using Student’s t-test, a one-way ANOVA test, Kruskal-Wallis test, or Mann-Whitney U test. The Mann-Whitney U test or Tukey’s test was used to determine the significance of pairwise differences. A Bonferroni correction was employed to adjust for multiple comparisons. Categorical data were compared with a χ² test. In addition, forward stepwise multivariate logistic regression models were created to identify the independent correlates of MTWA positivity. Variables with a p-value < 0.10 in the univariate analysis were included in the multivariate model. The statistical significance level was considered to be p < 0.05.