Aspirin is cheap, low-risk and taken by millions to reduce their risk of heart attack and stroke, not to mention alleviate the self-inflicted effects of hangovers. Now, recent developments have suggested it could help prevent and treat cancer, boost fertility and even play a role in dementia. So is this off-patent drug, made from the willow bark tree and discovered over 100 years ago – and which costs the NHS 3p per patient per day – set to become the super pill of the 21st century?
Last week, the world’s largest clinical trial on patients taking aspirin was launched to investigate whether it could stop cancers of the bowel, breast, oesophagus, prostate or stomach from returning. The Add-Aspirin trial on 11,000 people, funded by Cancer Research UK and the NHS, will last up to 12 years.
Meanwhile a US study has found that taking around a quarter of an aspirin daily could not only increase women’s chances of getting pregnant, it could also boost their likelihood of having a healthy baby.
Several other large-scale clinical trials are also set to report on aspirin’s benefits – or not – in the next decade. And already, last August, one study found taking low-dose aspirin daily could save over 6,500 lives from cancer per year and prevent nearly 500 fatal heart attacks.
Yet there are caveats: the research, from London’s Queen Mary University, reported side effects like severe stomach bleeding and ulcers led to nearly 900 deaths a year – prompting experts to warn the worried well that “anyone thinking of taking aspirin should talk to their GPs first.”
Here we look at how long-term use of daily, low-dose aspirin – 75 mg compared to 300mg in a typical headache pill – can benefit health.
“In trials looking at low-dose aspirin for cardiovascular disease, researchers noted less cancer developed and fewer people died from cancer too,” says Professor Ruth Langley of University College London and chief investigator in the new Add-Aspirin trial.
In one landmark study published in The Lancet in 2011 and led by Professor Peter Rothwell, a clinical neurologist at Oxford University and foremost researcher on aspirin, taken for at least five years in middle age it reduced the risk of developing gastro-intestinal cancers of the stomach, bowel and oesophagus by 20 per cent while also protecting against breast, lung and prostate cancers to a lesser extent.
Patients with cancer taking a daily aspirin had a 30-40 per cent reduced chance of their cancer spreading or “metastasising” to the brain, lungs or liver, further research from Prof Rothwell’s team found.
How does it work?
The answer lies with platelets, the little pieces in blood that make it sticky. When you’re on aspirin, your platelets are less sticky, so your blood is less likely to clot. “Platelets stick to cancer cells, making it difficult for the body’s immune system to clear them,” says Prof. Langley. “If they’re less sticky, cancer cells are more exposed so the immune system can identify and clear them.” Having less sticky blood could also make it harder for cancer cells to feed and grow, she explains.
Who should take it?
“If you have a family history of gastro-intestinal cancers of the bowel, stomach or oesophagus or you have had some screening and been found to have a polyp [small growth on the inner lining of the colon which can eventually turn into bowel cancer] then you may benefit,” says Prof Rothwell.
Last week, a global fertility expert recommended all women trying for a baby should take daily aspirin, calling it “the drug of the millennium.” Professor Richard Paulson of the American Society for Reproductive Medicine was responding to new research from Utah University that found women who took about a quarter of a typical aspirin (81mg) were more likely to conceive and have a successful birth after taking the aspirin – even though all 1,228 women in the study had had a miscarriage in the last 12 months.
Daily aspirin works by reducing inflammation, making the womb a safer environment for the embryo to implant and grow, the researchers said.
Who should take it?
Women with high levels of inflammation (something that can be measured with a simple blood test) who are looking to conceive may benefit, says Dr Nick Raine-Fenning, consultant gynaecologist at Nurture Fertility, Nottingham, and spokesman for The Royal College of Obstetricians and Gynaecologists. He wouldn’t advise all women trying to conceive to take a low dose aspirin without speaking to their doctors first though.
Daily aspirin can also help pregnant women at risk of pre-eclampsia, which affects eight per cent of pregnancies, is caused by high blood pressure and can lead to complications during pregnancy, he says. And it may be prescribed to women who have one of around 200 blood clotting disorders called thrombophilias that increase risk of recurrent miscarriage.
According to the Health and Social Care Information Centre, nearly 30 million prescriptions for low-dose aspirin were written in 2014 alone, most commonly to cardiovascular disease patients to help prevent the recurrence of a heart attack or stroke. For those with heart disease, there’s powerful evidence that taking daily aspirin can reduce the risk of having a further heart attack, says Dr Vinay Bhatia, consultant cardiologist at Spire Tunbridge Wells Hospital.
How does it work?
“Aspirin thins the blood and helps prevent it from clotting in blood vessels. This clotting causes heart attacks by stopping the supply of oxygen to the heart muscle,” says Dr Bhatia.
“If you have cardiovascular disease or have had a previous heart attack, taking a low dose of aspirin – 75mg – daily reduces your risk of having another,” says Dr Mike Knapton, associate medical director for the British Heart Foundation.
If you’re having a heart attack, chewing a 300 milligram aspirin – a tablet you’d take for a headache – can reduce your risk of dying by 25 per cent, he adds. “But don’t get up and start rummaging around for aspirin. Sit down, call 999 and if someone else can go get you one, that’s fine.”
Three in 10 stroke survivors will go on to suffer another. Aspirin is proven effective, and is widely prescribed, for preventing patients who have suffered a stroke or mini-stroke caused by a blood clot from having a second one, says The Stroke Association.
How does it work?
“Stroke normally occurs because you have developed a clot in a larger blood vessel in the neck, which then breaks off and lodges in the smaller artery in your brain,” says Dr Bhatia. Or, the clot may have formed somewhere else in the body and moved to the brain, he says. By preventing blood platelets from sticking together, aspirin makes this clotting less likely.
“All patients who have had thrombo-occlusive (ischaemic) strokes,” says Dr. Bhatia. “But not patients who have had haemorrhagic strokes – a bleed in the brain – as it can increase their risk.”
Some observational studies have suggested long-term use of aspirin is associated with a reduced risk of Alzheimer’s. One Swedish study found that women over 70 who took low-dose aspirin because they were at high risk of heart disease were found to have better memory and cognitive function after five years than those who didn’t.
Aspirin has been explored for use in vascular dementia too, the second most common cause of dementia after Alzheimer’s disease and caused by problems with the blood supply to the brain, says Dr Simon Ridley, director of research at Alzheimer’s Research UK. But, he cautions, there’s still not enough evidence to prove a beneficial impact.
A large-scale study in Australia called the ASPREE may change that. It’s currently following 16,000 Australians aged over 70 and on daily aspirin to investigate its role in Alzhemer’s, with results expected by 2018.
How might it work?
Researchers who say inflammation plays a role in Alzheimer’s believe an inflammation fighter such as aspirin may have benefits for the brain. As it thins the blood, it could help prevent clots in blood vessels in the brain too.
Who should take it?
No one, just yet. Some studies have found that 325mg of daily aspirin taken over three years could benefit people with vascular dementia but “more research is needed before aspirin can be recommended”, says Ian Le Guillou of The Alzheimer’s Society.
A daily aspirin isn’t a panacea for everyone. A small number of people will find it irritates their stomach, triggers allergic reactions or asthma, or causes indigestion and sometimes bleeding.
“If 100 people were to take aspirin for five years, around five to 10 of them would have minor bleeding such as a nose bleed,” says Prof Rothwell.
In one in 1,000 people this could be severe stomach bleeding and for around one in 10,000 patients on aspirin it could be a major brain haemorrhage. Such risks increase with age and are highest in those over 70.
Regarding pregnancy, “in some women aspirin may increase risk of miscarriage and bleeding or trigger asthma, so weigh up the risks with your doctor,” says Dr Raine-Fenning.