Do Acid Reflux Medications (PPIs) Raise Dementia Risk?

Omeprazole, Nexium, Prilosec — millions of people take a PPI every day for years without a second thought. Here's what the research on dementia risk actually shows, including where it flatly disagrees with itself.

What are PPIs, and why are so many people on them long-term?

Proton pump inhibitors reduce stomach acid production and are widely prescribed for acid reflux, GERD, and ulcer prevention — often continued for years without a formal reassessment.

Common PPIs include omeprazole (Prilosec, also available over-the-counter), esomeprazole (Nexium), pantoprazole (Protonix), and lansoprazole (Prevacid). They work by blocking the stomach's acid-producing pumps, which is highly effective for reflux, GERD, and preventing ulcers from other medications like NSAIDs. Because they work well and symptoms often return if stopped, many people end up on a PPI for years, sometimes without a doctor revisiting whether it's still the right choice or the lowest necessary dose — which is part of why questions about long-term PPI safety, including dementia risk, get asked so often.

What did the early research find?

A large 2015 South Korean cohort study first raised the dementia question, finding increased risk with PPI use after three or more years, particularly with omeprazole.

The initial concern came from a large South Korean population study of roughly one million people, which found an increased risk of developing dementia in PPI users after three years or more of use, with the association more pronounced for omeprazole specifically than for other PPIs. This study got considerable media attention and is likely the source of the question many caregivers are searching for today.

What does the more recent, larger evidence show?

Subsequent meta-analyses and a 2024 genetic study have not confirmed the original finding, with some larger analyses finding no association or even a protective one.

A comprehensive 2019 meta-analysis pooling ten independent studies and 642,305 participants found PPI use was not associated with dementia or Alzheimer's disease — directly at odds with the earlier single-country finding. A separate large-scale study using health data from Wales, UK also found no confirmed association between PPI use and increased dementia risk, and in that dataset, PPI use was actually associated with somewhat lower dementia risk, a finding researchers treat cautiously rather than as evidence PPIs are protective.

A 2024 Mendelian randomization study — a method that uses genetic variation to help distinguish a true causal effect from a coincidental association — concluded there was no robust direct causal link between PPIs and dementia risk. This kind of study design is generally considered stronger evidence against causation than a single observational cohort study is evidence for it.

So where does this leave a caregiver?

The dementia-risk question specifically looks weaker with more recent, larger evidence — but that doesn't mean long-term PPI use is risk-free in other ways.

Unlike anticholinergic drugs, where the dose-response relationship with dementia risk has held up across multiple large studies, the PPI-dementia link looks more like an early signal that didn't replicate as well in larger, more rigorous research. That's worth knowing if a caregiver has been quietly worried about a loved one's daily omeprazole. It's also worth knowing that long-term PPI use carries other, better-established risks worth discussing with a doctor: reduced absorption of vitamin B12 and magnesium, increased risk of bone fractures with long-term use, and a possible association with chronic kidney disease. None of these are about dementia specifically, but they're a legitimate reason to periodically ask whether continued use, and at what dose, is still the right call.

What to ask the doctor

The most useful conversation isn't about dementia specifically — it's about whether continued long-term use, at the current dose, remains necessary.

• Ask whether the original reason for starting the PPI is still present, or whether it was meant to be short-term and simply never revisited.
• Ask about the lowest effective dose, or whether an "as-needed" approach could replace daily use for milder symptoms.
• If long-term use is genuinely necessary, ask about periodic monitoring for B12, magnesium, and bone health.
• Don't stop a PPI abruptly after long-term use without guidance — rebound acid overproduction is common and can make symptoms temporarily worse.