GSTM1 and Cognitive impairment: For participants without cognitive impairment, there was a steep decrease in the risk of mortality with increasing Hb for concentrations <110 g/L (HR = 0.88; 95% CI, 0.79–0.98); for Hb concentrations above 110 g/L, the relationship was flattened (HR = 0.99; 95% CI, 0.92–1.06) (Figure 2A).