A comment by Dr. Charlie, biochemist.
Sorry for delay in getting back to you re TC/ apoB and Gabriella’s concern over a patient who had a blip in her LDL readings. In a way I’m glad that I did because just by chance I watched again the Wisdom of Clouds speech by Tom Naughton and the lecture by Prof Tim Noakes on YouTube, entitled “The Great Diet Controversy: UCT taught me to Challenge Beliefs”.
Although we could discuss the size and shape of the cholesterol bearing particles and whether it’s the number or total quantity that should be considered, I think that it is more important to consider whether the whole concept of the cholesterol hypothesis is correct. In the early days of the hypothesis many trials attempted but failed to establish a clear link between cholesterol and CHD – yet the medical profession were eventually persuaded that there was a very positive relationship.
I would agree with Noakes’ response to a question concerning cholesterol levels and say that women should not pay any attention to them – no work has shown any link for them and for men over 50, high cholesterol levels have been shown to be protective. For example, many studies, including the famous Framingham study begun in 1948, have shown that in people over 50/60, higher levels of cholesterol are protective (ie the death rate comes down with higher cholesterol). I just happen to have to hand the results of a recent Scandinavian study. This study published in the Scandinavian Journal of Health Care [I think that's the one - Ed] looked at the levels of cholesterol and risk of death in almost 120,000 adults living in Denmark.
The researchers found that having higher than recommended levels of total cholesterol was associated with a reduced risk of death. So they looked at the death rates amongst men who had a total cholesterol level of less than 5 mmol/l and compared that figure with the death rates of men who had total cholesterol levels between 5 and 5.99, and those between 6 and 7.99, and those with levels of 8 and above.
- They found that in men aged 60-70 when compared to those who had a total cholesterol level of less than 5...
- those with levels of 5.00-5.99 had a 32% reduced risk of death; and
- those with levels 6.0-7.99 had a 33% reduced risk of death.
Even in individuals with levels of 8.00 mmol/l and above, the risk of death was no higher than it was for those with levels less than 5.0 mmol/l.
The results were similar for women too. In women aged 60-70, levels of 5.0-5.99 and 6.0-7.99 were associated with a 43 and 41 per cent reduced risk of death respectively.
In individuals aged 70 and over, the results were similar, except here, levels of total cholesterol of 8.00 mmol/l or more were associated with a reduced risk of death too (in both men and women).
Together, these findings suggest that the current total cholesterol recommended by medics and other health professionals are way off beam. And the authors of this study suggested –rather meekly that - these associations indicate that high lipoprotein levels do not seem to be harmful to the general population.
So I hope you appreciate that for me the minutiae of particles may be of academic interest but not of medical interest – apart from the fact that higher levels are protective!
It has been 2007 since I have blogged on this topic, saying essentially the same thing, and nothing seems to change.
Thanks, Dr. Charlie!