Women who use antibiotics for more than two months are 35% more likely to suffer a heart attack or a stroke, study finds
- Experts at Tulane University believe long-term use of the drugs wipes out healthy gut bacteria
- The study is the largest long-term investigation of the link between antibiotic use and heart disease ever carried out
- That creates an imbalance that increases inflammation and narrows blood vessels
- The risk is highest for women over 60, and significant for women 40 to 59
- For younger women aged under 40, there was no discernible effect
Women who use antibiotics for more than two months at a time are at increased risk of suffering a heart attack or stroke, research suggests.
Experts believe the long-term use of the drugs wipes out healthy bacteria in the gut – creating an imbalance that increases inflammation, narrows blood vessels and ends up damaging the heart.
They think this creates a cumulative effect, so the more frequently a woman uses antibiotics during her lifetime, the greater the eventual risk.
The researchers, who tracked 36,500 women in the US, found over-60s who used antibiotics for more than two months were 32 per cent more likely to develop heart disease in the next eight years than those not taking the drugs.
The study is the largest long-term investigation of the link between antibiotic use and heart disease ever carried out
For those aged 40 to 59, there was a 28 per cent increased risk.
For younger women aged under 40, there was no discernible effect.
Researcher Dr Yoriko Heianza, from Tulane University in New Orleans, said: ‘By investigating the duration of antibiotic use in various stages of adulthood we have found an association between long-term use in middle age and later life and an increased risk of stroke and heart disease during the following eight years.
‘As these women grew older, they were more likely to need more antibiotics, and sometimes for longer periods of time, which suggests a cumulative effect may be the reason for the stronger link in older age between antibiotic use and cardiovascular disease.’
The researchers, who published their findings in the European Heart Journal, stressed that even though the overall relative risk increased, for each individual the absolute risk remained small.
For every 1,000 women taking antibiotics for at least two months, just six would be likely to experience damage to their hearts or arteries, they said.
Antibiotics are designed to kill dangerous bacteria that cause illness and infection.
But in the process they also destroy beneficial bacteria, altering the balance of the gut ecosystem and increasing the risk of viruses, harmful bugs and infectious fungal organisms.
Fellow researcher Professor Lu Qi, an expert in nutrition at Harvard School of Public Health, said: ‘Antibiotic use is the most critical factor in altering the balance of microorganisms in the gut.
‘Previous studies have shown a link between alterations in the microbiotic environment of the gut and inflammation and narrowing of the blood vessels, stroke and heart disease.’
The study is the largest long-term investigation of the link between antibiotic use and heart disease ever carried out.
The most common reasons for the women taking antibiotics were lung infections, urinary tract infections, and dental problems.
Professor Qi added: ‘Our study suggests that antibiotics should be used only when they are absolutely needed.
‘Considering the potentially cumulative adverse effects, the shorter time of antibiotic use the better.’
The NHS is desperately trying to reduce antibiotic use in a bid to avert the looming superbugs crisis.
This is because overuse of antibiotics triggers the evolution of harmful bacteria to resist treatment.
The more antibiotics are used, the stronger superbugs become – and yet no new class of antibiotics have gone on sale since the 1980s.
More than 3,000 people a year already die in Britain as a result of the superbugs crisis and the NHS spends £180million a year tackling the problem.