Coronary artery disease and cerebral artery disease are known as multifactorial diseases.
In the UK, we only intervene if your 10 years risk of an event is greater than 30% for cholesterol and 15% for raised blood pressure.
Our doctors take into account the following and plot them into a computer program or table
1 Age (younger is better)
2 Gender (female good)
3 Body mass index (25 or below is good)
4 Blood pressure ( 120/80 or lower is good)
5 Familial History ie mother /father/ sibling having an even before the age of 70 is bad
6 presence of diabetes is very very bad.
7 diet
8 excercise (more is better)
9 LDL level (high is bad)
10 HDL level ( high=good)
11 Smoking probably second only to diabetes as a risk
In general with strict diet you can probably move your cholesterol numbers by 10%. A good excercise program with increase HDL which is good. If you smoke, this must stop as it is worse than high cholesterol as a risk factor.
Omega 3 and Omega 6 fatty acids found in fish oil and olive oil may lower your LDL and are thought to offer some protection.
If you have genetic high cholesterol ,that is one of the familial types, diet will have zero effect.
And remember for most types of raised cholesterol, most of it is made in your own liver and not taken in in the diet.
A small increase in cholesterol in the absecnce of all other risk factors would not be treated here. Having said that, over here, the government picks up the tab and so sets guidlines for intervention a little on the high side.