1. Overview Standard descriptive summary statistics will be used for reporting continuous and categorical variables. In univariate analysis, inferential comparisons will be performed using analysis of variance or the Kruskal-Wallis rank sum test. Logarithm transformation may be used for highly skewed variables prior to inferential comparisons. Categorical variables will be analyzed with the use of Khi² or Fisher exact tests. Trends across ordered groups will be analyzed for statistical significance using the Khi² test for trends for categorical variables and the non-parametric Wilcoxon-type test for trends for continuous variables, respectively. Two-sided P values of less than 0.05 will be considered statistically significant.