GSTM1 and cardiovascular disorder: The risk of cardiovascular disease increased with baseline f-Hb, showing a significant elevated risk of cardiovascular disease in parallel with the incremental f-Hb with adjusted HR of 1.04, 1.10, 1.40, and 1.23 for f-Hb of 1–19, 20–49, 50–99 and ≥100 ng/mL, trend test, p < 0.0001, compared with the reference group with undetectable f-Hb.