The single largest cause of death for Americans is/are:

Coronary heart disease, also known as coronary artery disease (CAD), is the number one threat to American health, killing an estimated 466,000 persons annually. While some predisposition to coronary heart disease is non-modifiable, many of the risk factors are behaviors that can be changed (e.g., obesity, sedentary lifestyle, and smoking). While chronic obstructive pulmonary disease, cancer, and traumatic injuries represent major health problems, they do not claim lives on the same magnitude of coronary heart disease.