In a cohort study of 17,030 people aged 66 years and older, an inverse J-shaped relationship between Hb levels and all-cause mortality and the hospitalization rate for cardiovascular events was reported; the lowest risk for mortality occurred at Hb values between 13 and 15 g/dL for women and 14–17 g/dL for men, with or without chronic kidney disease (CKD) [3,5]. The gene discussed is GSTM1; the disease is chronic kidney disease.