Researchers link high levels of 'good' cholesterol with excessive mortality

August 23, 2017

It has been accepted wisdom for many years that the more good cholesterol people have in their blood, the better. But the good cholesterol, also known as HDL, might not be as good as we think.

In any case, the results of a new study from the University of Copenhagen seriously contradict the assumption that high levels of HDL in the blood are only a good thing. The researchers have shown that people with extremely high levels of good cholesterol have a higher mortality rate than people with normal levels. For men with extremely high levels, the mortality rate was 106 per cent higher than for the normal group. For women with extremely high levels, the mortality rate was 68 per cent higher.

"These results radically change the way we understand 'good' cholesterol. Doctors like myself have been used to congratulating patients who had a very high level of HDL in their blood. But we should no longer do so, as this study shows a dramatically higher mortality rate," says Børge Nordestgaard, Professor at the Department of Clinical Medicine and one of the authors of the study.

The researchers analysed data for 116,000 subjects from the Copenhagen City Heart Study and the Copenhagen General Population Study, in combination with mortality data from the Danish Civil Registration System. They have followed the subjects for an average of 6 years, and based the study on just over 10,500 deaths.

The researchers were able to calculate the mortality rate based on these deaths and medical information on the subjects. The results showed that men with extremely high HDL levels in the blood had a 106 per cent higher mortality rate than men with a normal HDL level. Among women, those with extremely high levels of HDL had a 68 per cent higher mortality rate than the normal group. Men in the next group, with very high levels, also had a 36 per cent higher mortality rate.

0.4 per cent of the men and 0.3 per cent of the women covered by the study had an extremely high level of HDL in their blood, and a further 1.9 per cent of the men had a very high level.

The study also found excessive mortality for people with extremely low levels of HDL in the blood. The people with medium levels of HDL in the blood had the lowest mortality. For men, this level was 1.9 mmol/L. For women, it was 2.4 mmol/L.

Earlier US studies have shown similar correlations between good cholesterol and excessive mortality among specific population groups, but this is the first time excessive mortality has been shown in the general population.

Professor Børge Nordestgaard, who also works as a consultant doctor at the Department of Clinical Biochemistry at Herlev and Gentofte Hospital, hopes the results can change our perception of HDL.

"It appears that we need to remove the focus from HDL as an important health indicator in research, at hospitals and at the general practitioner. These are the smallest lipoproteins in the blood, and perhaps we ought to examine some of the larger ones instead. For example, looking at blood levels of triglyceride and LDL, the 'bad' cholesterol, are probably better health indicators," he notes.

The new study examines the statistical correlation between mortality and HDL levels. It therefore cannot explain why people with extremely high or low HDL levels have higher mortality.
-end-
The study was conducted jointly by Dr Christian Medom Madsen and Dr Anette Varbo, and was funded by the Novo Nordisk Foundation and Chief Physician Johan Boserup and Lise Boserup's Fund. The study in the European Heart Journal is published in print on 23 August 2017.
-end-


University of Copenhagen The Faculty of Health and Medical Sciences

Related Cholesterol Articles from Brightsurf:

Cholesterol's effects on cellular membranes
The findings have far-reaching implications in the general understanding of disease, the design of drug delivery methods, and many other biological applications that require specific assumptions about the role of cholesterol in cell membranes.

Autism-cholesterol link
Study identifies genetic link between cholesterol alterations and autism.

Microbes might manage your cholesterol
Researchers discover a link between human blood cholesterol levels and a gene in the microbiome that could one day help people manage their cholesterol through diet, probiotics, or entirely new types of treatment.

Experimental cholesterol-lowering drug effective at lowering bad cholesterol, study shows
Twice-yearly injections of an experimental cholesterol-lowering drug, inclisiran, were effective at reducing low-density lipoprotein (LDL) cholesterol, often called bad cholesterol, in patients already taking the maximum dose of statin drugs, according to data of the ORION-10 trial presented Saturday, Nov.

Rethinking how cholesterol is integrated into cells
Cholesterol is best known in connection with cardiovascular disease, but cholesterol is also vital for many fundamental processes in the body.

Seed oils are best for LDL cholesterol
Using a statistical technique called network meta-analysis, researchers have combined the results of dozens of studies of dietary oils to identify those with the best effect on patients' LDL cholesterol and other blood lipids.

Cholesterol leash: Key tethering protein found to transport cellular cholesterol
Cholesterol is an essential component of living organisms, but the mechanisms that transport cholesterol inside the cell are poorly understood.

New way to treat cholesterol may be on the horizon
A breakthrough discovery by scientists at Houston Methodist Research Institute could change the way we treat cholesterol.

How low should LDL cholesterol go?
New analysis shows that in a high-risk population, achieving ultra-low LDL cholesterol levels, down to <10 mg/dL, safely results in additional lowering of risk of cardiovascular events.

Does boosting 'good' cholesterol really improve your health?
A new review addresses the mysteries behind 'good' HDL cholesterol and why boosting its levels does not necessarily provide protection from cardiovascular risk for patients.

Read More: Cholesterol News and Cholesterol Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.