Multivariable binary logistic regression model showed that WMH was significantly associated with age (p = 0.019), history of hypertension (p = 0.011), HHcy (p = 0.019) and MTHFR genotype (p = 0.041); while cognitive impairment was significantly associated with age (p = 0.033), history of hypertension (p = 0.019), HHcy (p = 0.040), MTHFR genotype (p = 0.039), WMH (p = 0.041), and lacunes (p = 0.001). The gene discussed is MTHFR; the disease is Cognitive impairment.