and those who did not have this information (did not participate in this study) were tested by the independent t-test.
Associations of Hb with the distributions of sFt and sTfR and the prevalence of low sFt and high sTfR were tested using linear regression analysis. Associations of sFt and sTfR between categories of Hb were tested by analysis of variance. Analyses were done using the SPSS for Windows software package (version 7.5.1; SPSS Inc., Chicago, IL, USA)