Pulse pressure (PP), the difference between systolic blood pressure (SBP) and diastolic blood pressure (DBP), arises due to pulsatile ejection of blood from the left ventricle. Previous observational studies have identified an inverse association of PP with aortic diameter1, and positive associations of PP with aortic wall stiffness and thickness2. However, it is not known whether these associations reflect a causal effect of PP on the risk of AAA, an effect of the aorta on PP, a shared etiology, or confounding from environmental factors.