The data gathered from the questionnaires and the results of the blood analyses were transferred to
the EpiInfo Software 2000 package (Epidemiological Program Office, CDC, Atlanta, GA, USA). The
statistical analysis was performed with the IBM SPSS Statistics Version 19 software for Windows.
The Fisher test and X2 were used to determine possible association between the nominal variables of
the study. The T-test or Mann-Whitney test was used for the comparison of the means. The level of
significance was set at 95% (p < 0.05).