Thus, the slope of the regression line between RDW as the dependent and Hb as the independent variable was reduced to the same extent in microscopy negative patients with persistent malaria as in the 405 patients with a positive microscopy compared to patients without malaria (Figure 2, red slope, purple slope, and green slope, respectively, P < 0.001 for the comparison between no malaria and both other groups). Here, GSTM1 is linked to malaria.