All analyses were performed using STATA
version 8.2, Texas, USA. 2007. The percentage of
musculoskeletal pain and other parameters were
calculated proportionally. Descriptive statistics
were percentages, and mean and standard
deviations (SD). The associations between
musculoskeletal pain and studied factors were
identified by using chi-square test and student ttest at 95 % confidence interval. This study was
approved by the appropriate institutional ethical
review committee, Khon Kaen University.