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This article waslast modified on 10 July 2017.

People with the highest plasma HDL cholesterol concentrations have the lowest risk of having a heart attack and vice versa. The current theory is that HDL cholesterol is ‘good’ because when high it lowers cardiac risk.

Our News item on 6 June 2012 described a large international study that showed people with inherited raised plasma HDL cholesterol concentrations had no reduction in cardiac risk. The trial of a new drug that increases HDL cholesterol was published online in the New England Journal of Medicine on 5 November 2012. The drug was given to half of more than 15,500 patients who had recently had an acute coronary syndrome. Over the next two and a half years the HDL cholesterol of the group given the drug rose between 31 and 40%. However, during that period the treated group had the same number of cardiovascular events and deaths as the group that did not receive the drug.

These studies show that neither inherited nor drug-induced increases in HDL cholesterol reduce heart attack risk. It seems that a higher plasma HDL cholesterol concentration is associated with a lower risk of heart attack because both result from healthy life style factors - not smoking, a sensible diet, maintaining a normal body weight and taking regular exercise.