To live a long life free of heart disease, what habits or conditions matter the most? According to a major global study, smoking and high blood pressure stand out as the two most important factors driving the risk of developing heart disease. Together with high cholesterol, excess weight (or being underweight), and diabetes, these five factors account for about 50% of the burden of cardiovascular disease, the leading cause of death worldwide. (Burden refers to all the negative effects — illness,