Is high cholesterol bad?
Many believe high cholesterol is bad, but this is simply not the case. The Framingham-study, which is the biggest cohort study on this question, finds no correlation between cholesterol and stroke risk. A metaanalysis of 45 cohort studies finds no correlation either.
Actually, high cholesterol is most likely good for you. It is protective for woman over 50. Low LDL-Cholesterol leads to a significant reduced cognitive performance and attentiveness. When having low cholesterol due to e.g. Statins while pregnant, it is highly probably that the child will have severe deformations. Mother’s milk is crammed with cholesterol, and for a good reason: it is assumed that high cholesterol is the reason nursed children develop a higher IQ. Low Cholesterol is a risk factor for depression and having nightmares.
I’ve got my cholesterol tested! Am I at risk?
In short, the only important factor is how many LDL particles (LDL-P) you have. Period. The parameters LDL cholesterol (LDL-C), Triglycerides, particle size matter only because they influence particle count (see below). When you have too many particles, you are at risk. If you do not know your LDL particle count, you simply do not know if you are at risk.
The ideal LDL particle concentration is below 1000 nmol/L. Above 1600 nmol/L means high risk.
That being said, a good predictor for LDL particle is the HDL to Triglycerides ratio. 1 is perfect, below 2 is good, above 3 means significant disease, above 5 means you will explode any moment.
How are LDL Cholesterol, LDL particle size, Triglycerides, and LDL particle count related?
Imagine your bloodstream is a highway. You want to move a given number of passengers (called Cholesterol) from A to B, with as few accidents (crashes into your artery wall that build up plaque) as possible. How can you do this?
When you have only few passengers (low LDL-C), you can get away with using small vehicles (small LDL-particles) to carry them because this will not lead to lots of traffic. When you have lots of passengers to move (high LDL-C) and still use small vehicles, you will need lots of vehicles (high LDL-P) hence get lots of crashes (increased risk of CHD).
When you have few passengers (low LDL-C) but large vehicles that can carry lots of passengers, your highway is empty and you will have hardly any crash. You can also get away with lots of passengers to move (high LDL-C) when your vehicles are big enough that your LDL-P stays reasonable.
Now this is not the whole story. We got other passengers as well (Triglycerides) who want to be moved around as well. These guys take away precious seats that could otherwise be used to carry cholesterol. When you have lots of Triglycerides to carry around you will need a higher number of vehicles to carry the same amount of cholesterol. Again, more vehicles means higher risk, so high Triglycerides drive high LDL-P.