MTHFR and sarcopenia: Binary logistic regression analyses with included additional covariates (age, sex, and physical activity) highlighted that with advancing age, sarcopenia was associated with MTHFR (AC + CC; OR = 2.645, 95% CI = 1.221–5.730, p = 0.014) and with ACTN3 (RX + XX; OR = 2.531, 95% CI = 1.018–6.291, p = 0.046) under a dominant model, and with MTHFR (CC; OR = 13.513, 95% CI = 4.8862–37.373, p < 0.001), with ACTN3 (XX; OR = 2.248, 95% CI = 1.020–4.957, p = 0.045), and with NRF2 (CC; OR = 2.196, 95% CI = 1.014–4.758, p = 0.046) under a recessive model (Table 1).