Contrary to current health wisdom, having high levels of good cholesterol (HDL-C) may actually be bad for your health.

An international study, led by researchers from the Perelman School of Medicine at the University of Pennsylvania and including researchers from the University of Glasgow, has shown that elevated levels of HDL-C may actually be bad for some people’s health.

The authors have shown that that a certain genetic cause of increased HDL-C may actually be “bad”. The mutation causes an increased risk of coronary heart disease even in the presence of elevated levels of HDL-C or “good” cholesterol. Their findings are published this week in Science.

University of Glasgow co-author Naveed Sattar, Professor of Metabolic Medicine, said: “These findings tell us much more about how HDL-C levels relate to heart disease. In most people, a high HDL-C is a good signal for their future risks, but in some people with very high levels due to a specific genetic cause, the reverse seems to be true, suggesting it’s more about how HDL particles function rather than its blood levels which cause or protect against heart disease.”Naveed Sattar

“These findings also reveal potential new ways to protect against heart disease by raising a level of protein which may in fact improve HDL function yet, paradoxically, lower its blood levels. More work is now needed to extend these exciting findings to the clinic”

Lead author Daniel J. Rader, MD, chair of the department of Genetics at the University of Pennsylvania added: “The thinking about HDL has evolved recently to the concept that it may not directly protect against all heart disease.

“Our results indicate that some causes of raised HDL actually increase risk for heart disease. This is the first demonstration of a genetic mutation that raises HDL but increases risk of heart disease.”

Previous research raised the possibility that HDL might not be quite as protective against heart disease as generally believed by cardiologists, especially after several clinical trials of HDL-raising drugs showed little or no effect.

“The thinking about HDL has evolved recently to the concept that it may not directly protect against all heart disease," said Dr. Rader. “Our results indicate that some causes of raised HDL actually increase risk for heart disease. This is the first demonstration of a genetic mutation that raises HDL but increases risk of heart disease.”

Rader and his colleagues sequenced the lipid-modifying regions of the genomes of 328 people with markedly elevated HDL (along with a control group with lower HDL) to identify genetic causes of high HDL.

The paper was published on March 10 in Science.

Media Enquiries: ali.howard@glasgow.ac.uk or elizabeth.mcmeekin@glasgow.ac.uk / 0141 330 6557 or 0141 330 4831

First published: 10 March 2016

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