Simplify the following text for a Grade 9 native English-speaking person.
Original: The 1987 report of National Cholesterol Education Program , Adult Treatment Panels suggest the total blood cholesterol level should be : 240 mg\/dL high cholesterol .
Simplified: Hypercholesterolemia means that cholesterol level is too high in the blood . Cholesterol levels that are high are possible precursors to heart disease .