NOX4 and hypertensive disorder: In this review, we summarized the current research regarding the association between risk factors for VaD and NOX: (1) Increased NOX expression was associated with the aging risk factor; (2) NOX activation produced intracellular H2O2, which induced vascular hypertrophy as a hypertension risk factor; (3) Increased activation of the NOX1, NOX2, and NOX4 isoforms was involved in ROS production and the development of the pathological condition in stroke risk factor; and (4) NOXs associated cognitive impairment was involved not only in vascular dementia but also in non-vascular diseases.