In the US, deaths from cardiovascular disease fell by about 50% in men and women between 1980 and 2000 and fell an additional 31% between 2000 and 2010. That's the good news, driven by the introduction of statin therapy and with more attention to risk factor modification.
The bigger issue now is what is the optimal screening age for CVD risk. There have been calls to screen patients as young as 21 to identify those with LDL cholesterol levels of over 190 mg/dL. A more recent recommendation from the US Government Preventive Services Task Force puts the age at 35 for men and 45 for women. In patients felt to be at high risk for CV disease, the age drops down to 20 for screening purposes. The magic number for the initiation of treatment seems to be 190 for the LDL (with the total cholesterol in the range of 280 or higher) even in patients with no documented atherosclerotic disease.
The optimal decrease percentage for the LDL cholesterol has not been clearly established but generally should follow a percentage of at least a 30-40% drop. Patients over the age of 75 should not be treated with statins unless they have proven atherosclerotic disease or have coexisting diabetes mellitus.
As can be seen by these above recommendations, there is not total unanimity about when to start treatment and how aggressive an approach to take. Much of the decision hinges on the input of the patient himself/herself as they may be facing a lifetime of taking a statin medication which can have side effects and yet undiscovered harmful effects. The facts however are indisputable. Statins can dramatically lower cholesterol levels and newer agents (PKCS9 inhibitors) show even more potent effects. If the drop in death rate seen in the early 2000's is any indicator of the beneficial effects from cholesterol lowering, these statistics can continue to show further favorable outcomes in lowering death rates from CV disease over the next 20 years.