Cholesterol-lowering drugs increase risk of diabetes, study finds

Published on Tuesday 16 February 2010 21:59

USING drugs to lower cholesterol increases the risk of developing Type 2 diabetes, research in Scotland suggests.

An analysis of 13 studies involving the drugs, known as statins, found that they increased the chances of someone developing diabetes by 9 per cent.

The researchers from Glasgow University said the benefits of the drugs still outweighed the slightly higher risk of diabetes because of the reduction in heart attacks and other health problems.

But they said the results raised questions about whether statins were appropriate for people at low risk of heart problems.

The research, published in The Lancet, looked at studies involving a total of more than 91,000 patients, of whom 4,278 developed diabetes. There was also a higher risk of Type 2 diabetes in older patients. The reasons behind the link between statins and diabetes remained unclear.

Professor Naveed Sattar, from the Glasgow Cardiovascular Research Centre, said: "On the one side we know that statins lower your blood cholesterol. They also improve your blood vessel function and dampen inflammation. All of these things may actually lower the risk of diabetes.

"On the other side, the two side effects we are aware of with statins are effects on the liver and muscles. These are two key organs in the development of diabetes. So, irritating liver and muscle ever so subtly may in some way affect the pathways relevant to the metabolism of sugar."

Prof Sattar said the effects of statins on muscles could explain the link with Type 2 diabetes, but this needed further study.

"One theory is that by affecting the muscles ever so slightly, it might make someone be slightly less active than they would be.

"We know that reduced activity ever so slightly – and this is speculative – might actually leave them to put on a tiny bit more weight than they would have if they weren't on statins.

"We are looking at this further to look at the net effect on weight of being on a statin compared to being on a placebo tablet."

Researchers pointed out that treating 255 patients with statins for four years would lead to one extra case of diabetes, but a one point drop in cholesterol levels in the same patients would cause a reduction of five "major coronary events", such as a heart attack.

Prof Sattar said: "For people who require statins for the right reasons, because they are medium to high risk (of heart problems], there's absolutely no worry whatsoever in the sense that the benefits substantially outweigh any small increase of diabetes by a long way.

"Where it may make a difference is people who are at very low risk of heart disease, who may want to take it over the counter just because they thought it might be a good idea.

"It may just make people look at prescribing statins carefully for the reasons we started prescribing statins – for medium to high risk of cardiovascular disease."

Dr Iain Frame, director of research at Diabetes UK, said: "This high-quality research has found a 10 per cent increased risk of diabetes in over 60s who take statins. This small increased risk, however, is heavily outweighed by the benefits of statins in those at high risk of heart problems."