Statins have no benefit for thousands of healthy older people taking them to prevent heart disease or stroke, according to research.
Many over-75s take the pills to protect against the risk of illness.
Yet the study suggests they only benefit those in this age group already with heart disease or type 2 diabetes.
Around six million UK adults take them. Experts say a further six million high-risk patients should too.
Statins cost 3p a day and lower bad cholesterol.
But the findings said there was “no evidence” that taking them for primary prevention in healthy over-75s prevents cardiovascular disease, the leading cause of death for this age group, or early death.
The five-year population study looked at 47,000 people in Spain. Diabetics aged 75 to 84 had a 24% lower risk of CVD with statins and a 16% lower risk of dying. The protective effect appeared to end by 90.
Dr Rafel Ramos, of Barcelona’s Jordi Gol Institute for Primary Care Research, said the study had “a large sample size, reflecting real-life clinical conditions”.
But Prof Colin Baigent, of the University of Oxford, said the use of routine health records was “a very unreliable way to determine effects of statins on the risk of heart attacks.
“Clinical trials have shown clearly that statins prevent heart attacks and stroke in over-75s, and benefits are similar irrespective of whether a person’s had a previous [one].”
Studies have shown patients on statins after a heart attack or stroke are 25% less likely to have another one or die early.