And the widespread use of statins, the cholesterol-lowering drugs, may have little or no benefit, the same study finds.

These conclusions are supported by a separate study, which criticises the new low levels of LDL (low-density lipoprotein) cholesterol being recommended by heart specialists. Researchers say that the drive to reduce LDL levels to just 70 milligrams/decilitre - the lowest-ever recommended levels for patients at highest risk - may be a wild goose chase, and that they would be better off by making lifestyle changes.

Researchers have discovered that patients with high levels of C reactive protein - which is generated during periods of acute inflammation such as with rheumatoid arthritis and lupus - are protected if they also have high cholesterol levels. Those who had low cholesterol levels were almost twice as likely to die from heart failure.

This discovery throws into question the use of statins, one of the most frequently subscribed drug groups in the world, as they may be putting at risk many people who are being protected by their high cholesterol levels.

Paradoxically, the only people who may benefit from statins are those who already have low LDL cholesterol levels.

Dr Andrew Clark, from Hull University and one of the research team members, said: "In contrast to what you might imagine, having a high level of cholesterol might be good for you."

In the same week, researchers from the University of Michigan have concluded that the new low levels for cholesterol have no scientific validity, but instead were perhaps arbitrary.

Rather than focusing on cholesterol levels, patients at risk should be advised to eat a healthier diet, and exercise more.

(Sources: World Congress of Cardiology, Barcelona (statins study); Annals of Internal Medicine, October 2, 2006, on line version (low cholesterol levels study)).