London, Dec 21 (IANS) Millions of people worldwide take cholesterol-lowering drugs known as statins to prevent heart attacks and strokes but a new study questions whether they actually work.

Hailed as ‘wonder pills’ by doctors and drug companies, other new evidence has linked statins with severe depression and suicide.

Statins are prescribed to anyone who is believed to have more than a 20 percent chance of a heart attack or stroke over the next 10 years, reports the Daily Mail.

It is hoped that, by lowering their cholesterol, the patients’ death risk will drop significantly.

A new study by the Johns Hopkins University, US, however, suggests a great many people may not benefit from statins – that’s because it’s our calcium levels, not cholesterol, that really matter.

Their study of 950 men and women found that statins may only help patients if they have a calcium build-up or calcification in their blood vessels, according to a Hopkins’s statement.

Calcium makes arteries harden and increases the risk of high blood pressure, heart attack and stroke.

Scientists believe calcification is primarily caused by a combination of genes and ageing, along with poor lifestyle such as lack of exercise, bad diet and smoking.

Michael Blaha of Hopkins, who led the study, said: ‘Our results tell us that only those with calcium build-up in their arteries have a clear benefit from statin therapy.’

These findings were presented at the American Heart Association earlier this month.