A follow-up study was done on 4807 patients who participated in the population-based Rotterdam study. These patients were followed from 1990-2000 and had no history of heart attack at the beginning of the study. In the group with the highest intake of Vitamin K2, the risk of dying from heart disease was decreased by 57% compared to those with the lowest intake. Also, intake of Vitamin K2 was associated with a 52% lower risk of calcification (plaque) in the aortic artery. Vitamin K1 was not associated with a protective effect, only Vitamin K2, also known as the menaquinones, had the protective effect.