‘Good’ cholesterol can be bad, says new study

A new study by an international team of researchers has found some people with high levels of “good” cholesterol are at increased risk of coronary heart disease, contrary to earlier evidence.

A new study by an international team of researchers that included noted cardiologist Nilesh Samani has found some people with high levels of “good” high density lipoprotein cholesterol (HDL-C) are at increased risk of coronary heart disease, contrary to earlier evidence.

Samani, who is based at the University of Leicester and was knighted in 2015, has been involved in major research, including the latest one published in the Science journal on Friday.

The discovery could move researchers away from potentially ineffective HDL-raising drugs to treat coronary heart disease, and lead to the development of new treatments to help reduce the risk of heart attack.

The researchers, including experts from the University of Cambridge, studied people with a rare genetic mutation in the SCARB1 gene, called the P376L variant, which causes the body to have high levels of “good” HDL-C, a Cambridge release said.

High levels of “good” cholesterol are commonly associated with reduced risk for coronary heart disease. Challenging this view, the researchers unexpectedly found that people with the rare mutation, who had increased levels of HDL-C, had an 80% increased relative risk of the disease – a figure almost equivalent to the increased risk caused by smoking.

Coronary heart disease involves the build-up of fatty material, or plaque, in coronary artery walls. If large quantities accumulate in the walls, blood flow to the heart can become restricted or blocked, increasing risk of a heart attack.

The team looked at the DNA of 328 individuals with very high levels of HDL-C in the blood and compared them to 398 people with relatively low HDL-C. As the P376L variant they found was so rare, they then looked at its effects on HDL-C and heart disease in more than half a million additional people.

Adam Butterworth, from the University of Cambridge and co-investigator of this study, said: “We found that people carrying a rare genetic mutation causing higher levels of the so-called ‘good’ HDL-cholesterol are, unexpectedly, at greater risk of heart disease. This discovery could lead to new drugs that improve the processing of HDL-C to prevent devastating heart attacks.”