For participants who had cognitive impairment, Hb levels were inversely associated with mortality for concentrations <150 g/L (HR = 0.83; 95% CI, 0.78–0.89); a positive but not significant association was noted for concentrations above 150 g/L (HR = 1.23; 95% CI, 0.99–1.53) (Figure 2B). Here, GSTM1 is linked to Cognitive impairment.