For heartburn sufferers, medications like Prilosec can be a saving grace. But a February 2016 study published in JAMA Neurology suggests they could be linked to serious conditions later in life.
Proton pump inhibitors (PPIs), such as Nexium, Prilosec, and Prevacid, were introduced in the 1980s to treat conditions like acid reflux, peptic ulcers, and gastroesophageal reflux disease (aka GERD). They are used by more than 15 million Americans to reduce stomach acid levels and ease painful symptoms like heartburn. But study researchers say that patients who use these drugs may be more likely to develop dementia as they age.
According to NPR, German researchers analyzed data from an insurance database to study 73,000 people over the age of 75 and found that people who took PPIs had a 44 percent higher risk of dementia compared to those who did not take PPIs. Though the research only established a link and not a direct cause, previous research found that PPIs boosted a brain protein in mice that also exists in large amounts in patients with dementia.
In an editorial accompanying the study, Lewis Kuller, MD, DrPH, from the University of Pittsburgh Graduate School of Public Health notes that the link might have more to do with old age than it does with any direct cause. Older people are more likely to take a combination of medications, and suffer from more diseases in general. And other studies have shown that people who take PPIs tend to be in worse health overall, and may be more likely to smoke cigarettes and drink alcohol, which increase risk for developing many chronic diseases.
Even still, Dr. Kuller notes that the study could affect how doctors prescribe PPIs. "This is a very important issue given the very high prevalence of pharmacological drugs' long-term use in elderly populations that have a very high risk of dementia," he writes. The study researchers recommend that doctors avoid overprescribing PPIs and make sure they're being used appropriately.
Procter & Gamble, the maker of Prilosec, responded in a statement that its drug is "safe and effective," and people who are concerned should talk to their doctors. AstraZeneca and Takeda, the makers of Nexium and Prevacid, respectively, did not respond to Fortune's request for comment.