More people over the age of 75 should be taking statins, scientists have said, following a review of research.
There had been a lack of evidence about how much the cholesterol-lowering drugs benefit this age group.
But the review found they cut the risk of major cardiovascular disease in all ages studied, including the over-75s.
Researchers said thousands of lives could be saved each year if more than the estimated third of UK over-75s who do take statins, were given them.
They also said it could improve quality of life for many people.
Cardiovascular disease kills about 150,000 people in the UK each year, with two-thirds of these occurring in people over the age of 75.
Statins reduce the build-up of fatty plaques that lead to blockages in blood vessels, though reported side effects and the extent of how often they are prescribed has attracted controversy.
Side effects 'massively outweighed'
The review, which looked at 28 randomised controlled trials - often called the "gold standard" of studies - involving nearly 190,000 patients, found statins lowered the risk of major cardiovascular disease in the ages studied, from under-55s to over-75s.
There were similar reductions in risk for stroke and for coronary stenting or bypass surgery.
Authors of the paper said there had until now been an "evidence gap" around how effective the drugs are for the elderly.
They estimate that about a third of the 5.5 million people in the UK over 75 take a statin, when the "vast majority" of these would meet the medicine regulator's guidelines for being prescribed the drug.
Prof Colin Baigent, one of the authors of the paper, said: "One of the issues we have is that very often doctors are unwilling to consider statin therapy for elderly people simply because they're old, and that, I think, is an attitude that is preventing us from making use of the tools we have available to us."
The benefits were strongest in people who have already had vascular disease. There wasn't enough data in people over the age of 75 who haven't had it to show a benefit. Experts have called for more data to guide prescription for these people.
However, the authors said even a smaller reduction in risk was significant because the elderly have a higher baseline risk for cardiovascular disease in the first place.
The more people reduced their low-density lipoprotein (LDL), or "bad" cholesterol, the more the risk of cardiovascular disease was lowered, the study found.
A 1.0 mmol/L reduction in LDL cholesterol lowered the risk of major vascular events by about a fifth and a major coronary event by a quarter, when results from all age groups were combined.
To put this into perspective, about 2.5% of 63-year-olds with no history of vascular disease would be expected to have their first major vascular event per year, compared with 4% of 78-year-olds.
Reducing those risks by a fifth would prevent first major vascular events from occurring each year in 50 people aged 63 and 80 people aged 78 per 10,000 people treated.
Prof Baigent said there was an argument for giving statins to people over the age of 75 who have a "normal" level of LDL cholesterol.
He said: "In many circumstances, the person may be very healthy, they may be able to avoid having a stroke or having a heart attack simply by taking a cheap and safe tablet every day.
"That may be a choice they're willing to take. At the moment I feel we're not taking the opportunity to offer that."
There has been controversy about statin side effects and how often they are prescribed, especially in otherwise healthy people.
Common side effects include muscle pain, increased risk of type 2 diabetes and digestive problems.
It is possible to lower cholesterol levels without drugs by making lifestyle changes, such as by cutting down on saturated fat and eating more fruit, vegetables and fibre.
Prof Baigent said side effects were "massively outweighed, both in middle age and the elderly, by the benefits of statin therapy that we already know about".
And he also said he was not calling for people to pick statins over exercise and lifestyle changes.
"I think it's not an either/or," he added.
The Royal College of GPs welcomed the research and said it was "particularly reassuring" to see evidence of the benefit of statins in over-75s.
Prof Martin Marshall, vice-chairman of the college, said some patients would not want to be on long-term medication.
"But GPs are highly trained to prescribe and will only recommend the drugs if they think they will genuinely help the person sitting in front of them, based on their individual circumstances - and after a frank conversation about the potential risks and benefits."