Statistical Analysis
The Community, Environmental and Occupational Medicine Department of Ain Shams University suggested a minimum sample size of 36 patients in each group to get reliable results. The collected data was revised, coded, tabulated, and introduced to a PC using the Statistical Package for the Social Sciences (SPSS 15.0.1 for windows; SPSS Inc, Chicago, IL, 2001). The variables are reported as mean ± standard deviation (SD), median and interquartile range (IQR), or number (N) and percentage. Suitable analysis is done according to the type of data obtained. An independent t-test, chi-square test, and Mann-Whitney U test are used to analyze data accordingly. P-value <0.05 is considered statistically significant.