GSTM1 and hip fracture: Among patients with hip fracture, Hb levels below 100 g/L accounted for 21.3%,and some studies have used a cut-off value of less than 100 g/L to determine low Hb levels at admission, so we chose Hb levels below 100 g/L as the cut-off [27, 28]..Looker AC et al. A non-linear association between hemoglobin and the risk of hip fracture was discovered [29].