A day or so ago I received this e-mail from a doctor in London.
Dear Dr Kendrick,
I work as a GP in Wandsworth London and I read that you don’t
believe that much in cholesterol and CHD.
I do agree up to 50% of MI patients have normal cholesterol
but some say what’s normal for UK is actually high. Is this argument valid?
Define ‘normal.’ Does normal mean average? If we took the average height of everyone in the UK we would find (very nearly) that 50% of those dying of CHD (coronary heart disease) were above average height and 50% below. So average is clearly normal, but then again so is being tall, or short.
However, if we decided that average height of everyone living in the UK was above ‘normal’, and we then lowered the definition of ‘normal height’ by three inches, we would find that the vast majority of people dying of CHD were now above average height. At which point we could decree that being taller than normal was a risk factor for CHD.
This would obviously be a completely bonkers thing to do. Yet, you can do it with cholesterol levels and everyone nods in general agreement.
Aha, but the argument goes that our lives are completely different than the lives of our ancestors, which has caused our cholesterol levels to be unnaturally high.
An article in the Journal of the American College of Cardiology best summed up this line of thinking. Under the heading ‘Why average is not normal’, O’Keefe, the lead author, made the claim that: ‘Atherosclerosis is endemic in our population, in part because the average LDL (“bad” cholesterol) level is approximately twice the normal physiologic level.’ In short, according to O’Keefe, our cholesterol level should be about 2.5mmol/l, not 5.2mmol/l.
He based his argument, in part on looking at the cholesterol levels of various animals e.g. elephants, and boars, and suchlike. He also used the argument that very young babies (neonates) have cholesterol level of about 2.5mmol/l. Now, in my opinion, anyone proposing this argument should have their medication increased. We should base our cholesterol levels on those found in other animals species….yes, of course we should. You mean those animal species with an average life expectancy of ten years, for example.
However, this argument is now pretty widely accepted by the medical community. We are all, everyone, living in the West, living in such an ‘unhealthy’ way that our cholesterol levels are unnaturally high. The true normal cholesterol levels is 2.5mmol/l.
Fine, if we re-set normal at 2.5mmol/l we will find that 99% of people dying of heart disease do have a ‘high ‘cholesterol level. Problem sorted, average is no longer normal, and the hypothesis that a high cholesterol level is a risk factor for heart disease is now true.
Hold on, I’ve got an idea…