 Statistical analysis: Statistical analysis will be carried out by Statistica 9.0 software. Significance level will be considered p 0.05. The qualitative variables will be expressed as counts and percentages. The quantitative continuous variables will be expressed as means and standard error of means M m for variables that meet the criteria of normality and minimum and maximum, median for those that do not meet the criteria of normality. Kruskal-Wallis test will be used for comparing multiply independent samples and Mann-Whitney U test for comparing two independent samples if variable under consideration will continuous and that it will be measured on an ordinal scale. For comparisons of proportions, the Chi-square will be used. 