Scientists have discovered how over-the-counter tablets, taken by millions of Britons, dramatically increase the risk of stomach cancer.
A study conducted by the University of Hong Kong and University College London found, people who regularly use proton pump inhibitors, known as PPIs, are eight times more likely to develop the cancer.
The common drugs are used to treat acid reflux and are twice as likely to cause stomach cancer – a risk which soars to eight-fold after three years of taking the pills.
It’s estimated five million bottles and packets of the drugs are prescribed each year in England, to treat the condition known as gastroesophageal reflux – a severe form of heartburn.
In addition to this, thousands more buy them over the counter at pharmacies, corner shops and supermarkets without the need of a prescription.
Although they’re not recommended for long-term use, the scientists fear because the pills are so easily available, people can easily take them for years without any medical supervision.
The researchers suspect the pills stimulate a hormone known as gastrin, which triggers the growth of cancerous cells.
The new study involved 63,000 people in Hong Kong who were treated with antibiotics which killed bacteria known as H. pylori – which is linked to stomach cancer, at the start of the research.
They were then tracked for an average of seven years and due to the antibiotics, the scientists ruled out the bacteria developing the cancer.
Those who took the pills at least weekly were found to be more than twice as likely to develop the cancer compared to those who didn’t use the drugs.
Daily users saw their risk increase 4.5 times and the longer the people took the drugs, the more the risk grew, soaring to 8.3 times for those who took the pills daily for at least three years.
Those who took an alternative treatment known as H2 blockers saw no increased risk.
The study said:
The patients were monitored on average for 7.5 years until they either developed stomach cancer, died or the study concluded, which was at the end of December 2015.
During this time, 3271 (5%) people took PPIs for an average of nearly three years and 21,729 took H2 blockers.
In all, 153 (0.24%) people developed stomach cancer after triple therapy.
None tested positive for H. pylori at the time, but all had long standing gastritis which is inflammation of the stomach lining.
Taking PPIs was associated with a more than doubling (2.44) in the risk of developing stomach cancer, while taking H2 blockers was not associated with a heightened risk.
The scientists also stressed although the increased risk is indeed dramatic, only a few people get stomach cancer.
In their research, out of the 63,397 people studied, only 153 actually developed the disease.
The study calculated how from their results, for every 10,000 people who take PPIs, an estimated eight people a year will develop stomach cancer, only four more than if none were taking the pills.