Statins not only lower cholesterol but can improve the structure and function of the heart, research has shown.

People taking the drugs were less likely to have abnormally enlarged hearts, a sign of stress and weakness, scientists said.

Investigators used magnetic resonance imaging (MRI) to scan the hearts of 4,622 British participants, nearly 17% of whom were on statins.

Compared with untreated individuals, patients prescribed the medicines had lower left ventricular heart chambers containing 2.4% less muscle mass. Their lower left and right ventricular volumes were also reduced.

Lead scientist Dr Nay Aung, from Queen Mary, University of London, said: “People using statins were less likely to have a thickened heart muscle (left ventricular hypertrophy) and less likely to have a large heart chamber.

“Having a thick, large heart is a strong predictor of future heart attack, heart failure or stroke, and taking statins appears to reverse the negative changes in the heart which, in turn, could lower the risk of adverse outcomes.”

He added: “It is important to note that in our study, the people taking statins were at higher risk of having heart problems than those not using statins, yet they still had positive heart remodelling compared to the healthier control group.”

The findings were presented at EuroCMR 2017, a conference on heart imaging taking place in Prague, Czech Republic.

Previous research had suggested that statins reduce the thickness of heart muscle, but the evidence needed to be confirmed in a larger study, Dr Aung said.

Scientists took account of other factors that can affect the heart, including ethnicity, gender, age and body mass index (BMI).

Additional beneficial effects of statins include improved blood vessel function, reduced inflammation, and the stabilisation of fatty deposits on artery walls.

Several studies have shown that statins reduce oxidative stress and the production of growth factors, natural chemicals that stimulate cell growth. This may have a bearing on their effect on heart structure, Dr Aung pointed out.

Statins also helped to dilate blood vessels leading to improved blood flow and lower stress on the heart.

Dr Aung said he was not in favour of offering statins to everyone over the age of 40.

“There are clear guidelines on who should receive statins,” he said. “There is debate about whether we should lower the bar and the question is when do you stop.

“What we found is that for patients already taking statins, there are beneficial effects beyond cholesterol lowering and that’s a good thing. But instead of a blanket prescription we need to identify people most likely to benefit, ie personalised medicine.”