A compelling new study published in the British online journal, Gut, has found that long-term use of proton pump inhibitors (PPIs) following Helicobacter pylori (H pylori) elimination therapy increases stomach cancer risk. H pylori is a commonly found bacteria in the digestive tract that is known to cause stomach ulcers.

Millions of Americans use PPI medications each year. PPIs are typically prescribed by doctors to treat chronic acid reflux and heartburn. They work by preventing the cells in the lining of your stomach from over-producing acid. The most common over-the-counter PPIs include Prilosec and Nexium.

Published by the British Society of Gastroenterology, Gut reported that the subjects of the study conducted in Hong Kong were “adults who had received an outpatient prescription of clarithromycin-based triple therapy between year 2003 and 2012.”

During the study, 3,271 subjects took PPIs for an average of three years, and 153 of them developed stomach cancer within an average of five years of completing the triple therapy. Upon receiving a cancer diagnosis, none of the patients tested positive for H pylori, but they had already suffered for years with stomach lining inflammation.

The researchers have stressed this is only an observational study, and no cause and effect has yet been proven, but doctors should “exercise caution when prescribing long-term PPIs … even after successful eradication of H pylori.”

According to The Guardian, “daily use of PPIs was associated with a risk of developing [stomach cancer] that was more than four times higher (4.55) than those who used it weekly.”
It’s an alarming finding, considering gastric cancer is the third leading cancer-related cause of death in the world, and the FDA added a warning to Nexium in 2014 of “atrophic gastritis” due to long-term Nexium consumption of three years or more.

Just last year, Nexium earned more than $2 billion in revenue for manufacturer AstraZeneca.