London, Aug 24: While high levels of "good" cholesterol have long known to be beneficial, its excess can also raise your risk of death, researchers claim. Cholesterol is a fatty substance known as a lipid and is vital for the normal functioning of the body. However, the findings showed 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 the normal group, while for women it was found to be 68 per cent higher. "These results radically change the way we understand 'good' cholesterol. Doctors 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," said Borge Nordestgaard, Professor at the University of Copenhagen in Denmark. For the study, the team analysed data of 116,000 people. They were followed for an average of six years and the result showed over 10,500 deaths. On the other hand, people with extremely low levels of HDL in the blood were also at increased risk of mortality, the researchers said. 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. "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," Nordestgaard said.