Chi-square test and F-test were used for qualitative data and Separated multivariable logistic regression models
were used to assess the associations between the prevalence in each body region and statistically significant factors.
Backward selection procedures were used in the statistical modelling. The odds ratios (ORs) associated with
particular factors were adjusted for the effect of all other factors that were in the model. Adjusted ORs and 95% CI
for the final models were presented in the results section. All statistical analyses were performed using the SPSS
statistical software, version 21.0.