Almost all men over 60 and women over 75 are eligible for statins, according to a new analysis.
After examining guidance on which patients should be offered stain therapy, researchers calculated 11.8 million English adults are eligible for the cholesterol-lowing drugs.
This works out to be more than a third (37%) of people between the ages 30 and 84, the researchers said.
Of these, 9.8 million would be offered the medication as a preventative measure.
And among this group, the researchers said 6.3 million were eligible for treatment but not currently on statins.
The authors calculated that if all these people were taking statins 290,000 cardiovascular events - including heart attacks and strokes - could be prevented over the next decade.
The team of researchers, led by Peter Ueda of the Harvard TH Chan School of Public Health in the US, set out to investigate the implications of guidance set by the National Institute of Health and Care Excellence (Nice) in 2014.
The guidelines, which have received much debate, expanded the number of people eligible for statin therapy on the NHS.
NICE said people without cardiovascular disease (CVD) should be offered the medication if they are deemed to have a 10% or higher chance of developing CVD within 10 years.
Previous guidance recommended treatment for people with a 20% or higher risk.
Patients with existing CVD should also be offered statins.
The latest study, published in the British Journal of General Practice, examined the algorithm endorsed by Nice for the assessment of CVD risk and compared it to data from the 2011 Health Survey for England to estimate the number of people who are eligible for statin therapy under the guidance.
"Under the guidelines, 11.8 million (37%) adults in England aged 30-84 years, including almost all males over 60 years and all females over 75 years, would be eligible for statin therapy," the authors wrote.
They found most adults who were eligible or treated for primary prevention were in older age groups.
Just 4% of men and 2% of women aged 30 to 44 were deemed to be eligible to be offered the medication, but this figure increased with age.
Among men, 33% of those aged 45 to 59 would be eligible according to the risk assessment tool.
This increased to 95% of men aged 60 to 74 years and 100% of men aged 75 to 84.
One in 10 women aged 45 to 59 would be eligible, increasing to 66% of women aged 60 to 74 and 100% of women aged 75 to 84.
Professor Mark Baker, director of the centre for guidelines at Nice, said: "Heart disease and stroke are largely age-related, killing one in three of us and disabling many more.
"To make progress in the battle against heart disease and stroke, we must encourage exercise, improve our diets still further, stop smoking, and where appropriate offer statins to people at risk.
"Their use in people who have established cardiovascular disease is not controversial. Their use to prevent the development of cardiovascular disease in well people is a more recent role but is equally widespread and robustly evidence-based.
"NICE's guidance on reducing cholesterol recommends that doctors should offer statins to people with a 10% risk of developing cardiovascular disease over 10 years. The purpose is to reduce further the numbers of people suffering heart attacks and strokes.
"But people, including older people, should not take statins instead of making the lifestyle adjustments that those at risk of cardiovascular disease need to make - such as stopping smoking, being more active, drinking less alcohol, eating more healthily and losing weight."
Commenting on the paper, Professor Helen Stokes-Lampard, chairwoman of the Royal College of GPs, said: "Statins have been found to be highly effective drugs at preventing cardiovascular disease by reducing cholesterol levels of patients, and extensive research has shown that taking them is safe.
"But our patients should only take medication if they need to, and specifically they are at high-risk of developing conditions that statins can help prevent.
"We need to get the risk scores right. If we find that all men over 60 and all women over 75 are going to be eligible for statins with new risk scoring, regardless of any other risk factor, then it should ring alarm bells - because it is not clear that every 60 year old man or 75 year old woman is going to benefit from statin therapy.
"As with any drug, taking statin medication has potential side-effects, and taking any medication long term is a substantial undertaking for patients.
"Many don't want to take statins once they have learned all the facts - and GPs will respect patient choice."
Dr Mike Knapton, associate medical director at the British Heart Foundation, added: "There is no question that statins lower people's risk of heart attack and stroke.
"This study suggests that an estimated 6.3 million people are missing out on the potential lifesaving benefits of statins. If these people were taking statins, we could not only potentially prevent 290,000 heart attacks and strokes, but also reduce the burden of these events on both the NHS and people's lives.
"We already know that heart attack and stroke are more common as you get older, which is why it's so important to address risk factors at a young age.
"Thanks to the NHS Health Check programme, all adults over the age of 40 can have a free health check to find out if that are at risk of developing cardiovascular disease. As well as taking statins, keeping active, eating a balanced diet and not smoking are vital to lowering your risk and keeping your heart healthy."
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