MTHFR and hypertensive disorder: When included in the multivariable model, age (65–74 years, OR: 2.530, 95% CI: 1.213 to 5.279, p = 0.013; ≥75 years, OR: 2.860, 95% CI: 1.201 to 6.809, p = 0.018), history of hypertension (OR: 1.977, 95% CI: 1.170 to 3.341, p = 0.011), HHcy (OR: 2.201, 95% CI: 1.139 to 4.251, p = 0.019) and MTHFR TT genotype (TT genotype, OR: 2.706, 95% CI: 1.096 to 6.685, p = 0.031) remained significant (Table 4).