Nov. 1 (UPI) -- A study at University College London and the University of Hong Kong suggests long-term use of a drug for acid reflux may double the risk for stomach cancer.
Researchers found that long-term use of proton pump inhibitors to treat acid reflux can significantly increase a person's risk of stomach cancer, the latest negative health effect that has been linked to the drugs.
PPIs have been linked to pneumonia, heart attack and bone fracture. And a previous study of long-term use of common PPIs, such as Nexium, Prilosec and Prevacid, suggested they could potentially increase a person's risk for early death.
For the current study, published Tuesday in Gut, researchers found the risk of developing stomach cancer increased with dosage level and duration of treatment with the drugs, which eliminate Helicobacter pylori, a bacteria associated with the development of stomach cancer.
Even though the elimination of H. pylori from the gut lowers a person's risk of stomach cancer, a large number of people still develop stomach cancer.
"Proton pump inhibitors [PPIs] are important treatment of Helicobacter pylori infection and have good safety records for short-term use," Ian Wong, professor at the UCL School of Pharmacy, said in a news release. "However, unnecessary long-term use should be avoided."
The study was observational in nature so researchers caution that no firm conclusions can be made regarding cause and effect.
Researchers compared the use of PPIs with a histamine H2 receptor antagonist, another drug to reduce acid production, in 63,397 adults who were treated with a PPI and two antibiotics to kill off H. pylori over a seven-day period.
Results showed 0.24 percent of participants developed stomach cancer after the triple therapy, none tested positive for H. pylori. PPIs were linked to a more than doubling of the risk of stomach cancer, but taking H2 blockers was not found to result in an increased risk.
Long-term use was linked to a higher risk of developing stomach cancer, with patients taking PPIs for more than a year having a five times increased risk, two or more years with a six times higher risk, and three or more years with an eight times higher risk.