In the last few weeks I’ve been asked about high cholesterol by family and fellow doctors.
Now that cholesterol checks are so easily done, the harder thing is understanding the result and what that means for you.
A bit of background – cholesterol is a fat that is necessary for the walls of all cells. It is carried around the bloodstream in 2 different types of proteins – Low density (LDL) and High density (HDL).
High LDL levels are associated with a higher risk of heart attacks, strokes and peripheral vascular disease.
Higher HDL levels seem to be protective.
So the first thing to look at when the total cholesterol is high, is to look at the breakdown into HDL and LDL.
What to do about high LDL levels? It depends on the overall risk of problems.
In the UK the 10 year risk is usually estimated using the Qrisk calculator. The main determinant of risk is age and you can plug your numbers into the online calculator (qrisk.org).
People in their 40’s are likely to be at lower risk, particularly if you don’t smoke, don’t have diabetes and exercise regularly.
There is good evidence that if your risk of running into problems over the next 10 years is high, then using statins can lower that risk by 20-30%.
However most trials have focussed on people with a high risk of problems. This is obviously because these people have the most to gain, and it’s the easiest to demonstrate a difference with treatment.
For example, the WOSCOPS study in Scotland enrolled patients with an LDL > 4mM (average 5mM) and lowered it to 3.9 with 5 years of pravastatin and demonstrated a significant reduction in cardiovascularly endpoints and a nearly statistically significant reduction in mortality. (P=0.051). Benefits were maintained out to 15 years.
The Jupiter study looked at people with a mean LDL of 2.8mM and an elevated CRP (>2) suggestive of inflammation, and did find a small benefit.
Current recommendations suggest it is not worthwhile treating patients with a patient 10 yr risk <5%(European guideline), and do suggest treating if risk is >7.5% (US guideline) or >10% (NICE UK guideline)
Lowering LDL with lifestyle measures or non-statin drugs has not been proven to reduce risk. The data regarding dietary measures indicates that most people can lower their LDL by ~5%, but if you have a bad diet to start with you can see reductions of up to 30%.
There’s no real data about long term statin therapy to extrapolate results from shorter term trials. It’s also unknown if treating patients earlier is better than leaving treatment until risk increases.
So to sum up I personally wouldn’t panic if my cholesterol were high – I would consider getting a high sensitivity CRP test (one that can detect a level of <5) and check your Qrisk score. And be sensible about lifestyle – at least half an hour of brisk walking a day, not too much salt or alcohol, and a balanced diet with plenty of vegetables and fish.