The J-curve phenomenon shows the direct relationship between having high blood pressure and/or high cholesterol and mortality. When the blood pressure or cholesterol levels of large groups of people are plotted on a graph against cardiovascular disease mortality, a J-shaped curve is often formed. This shows how people with higher blood pressure and/or cholesterol are closer to the top of the curve, illustrating that their risk of dying from a cardiovascular disease is much greater than those with normal blood pressure and choesterol levels. The J-shape curve also indicates that the people who appear closest to the bottom of the curve, or those with unusually low blood pressure and cholesterol levels are also more likely to contribute to the cardiovascular disease mortality rates than those with regular, controlled levels of cholesterol and blood pressure.