A medication sitting in tens of millions of bathroom cabinets right now – taken daily, often for years, considered so routine that many people refill it without a second conversation with their doctor – has been linked in a major peer-reviewed study to a significantly elevated risk of dementia. Not a fringe finding. Not a small-sample preliminary result. A 33 percent increase in dementia risk, drawn from a longitudinal community-based cohort tracking thousands of adults across decades. The kind of number that, once you see it, tends to follow you around.
The drug in question is one of the most commonly dispensed in the developed world. It is commonly prescribed to provide short-term relief for peptic ulcers and gastroesophageal reflux disease, better known as GERD. Millions of people take it every morning without giving it much thought. It is available by prescription and over the counter, often under brand names that have become household words. And for most people who genuinely need it for a defined, short-term problem, the benefit likely outweighs any risk. The complication – and the reason this finding matters – is that a very large proportion of people taking this drug are not using it short-term.
Over the past decade, the use of this drug class has increased significantly, with over half of its prescriptions not linked to a documented diagnosis of a gastrointestinal problem. That is the context this research arrived in, and it is the reason physicians and pharmacists have begun to look at it with considerably more attention.
What the Study Found
The research specifically examined whether current and cumulative use of the medication increases the risk of incident dementia, drawing on the Atherosclerosis Risk in Communities (ARIC) Study – a long-running, community-based cohort that began enrollment in 1987. This is not a small or hastily constructed dataset. A total of 5,712 dementia-free participants with a mean age of 75.4 years, 58 percent female, were included in the analysis, with a median follow-up of 5.5 years.
The minimum cumulative use recorded among participants was 112 days, and the maximum was 20.3 years. There were 585 cases of incident dementia identified during follow-up. The study’s central finding, published in the journal Neurology, was precise in its conditions: those who used the medication for more than 4.4 cumulative years before the study’s baseline visit were at a 33 percent higher risk of developing dementia during follow-up, compared to those reporting no use.
Associations were not significant for lesser durations of use. That is a finding worth reading twice. Taking the drug for a year, or even several years, did not produce a statistically meaningful association with dementia in this analysis. The elevated risk appeared specifically with long-term, cumulative exposure – crossing the four-year threshold. Current and short-term use of the drug was not significantly associated with increased risk of dementia.
The Dementia Risk Medication Debate: What We Know and What We Don’t
The 33 percent figure requires careful handling. Study limitations included lack of adjustment for all potential confounding factors, lack of generalizability outside of Black and White racial populations, and the inability to continuously measure drug use throughout the duration of the study, especially given its over-the-counter availability. The researchers themselves noted the need for further study to understand the pathways involved.
Significantly, a 2025 updated meta-analysis published in PMC – which is the most comprehensive overview of the existing evidence – found a more cautious picture overall. Eighteen studies encompassing more than 6.3 million participants met the inclusion criteria, and the pooled estimate showed no statistically significant association between use of this drug class and overall dementia risk. The evidence, at the broadest level, remains inconsistent across studies.
But the meta-analysis also identified something important within the inconsistency. Subgroup analyses revealed significantly elevated risks among individuals aged 65 years and older, and in studies from Asia and Europe, suggesting possible population- or context-specific vulnerability. The researchers concluded that there is a lack of consistent evidence supporting a link between use of the medication and dementia risk, primarily due to significant variation among existing studies – but that significant subgroup signals in older adults suggest clinical uncertainty remains.
That phrase – clinical uncertainty – is important. It does not mean there is nothing to see here. It means the picture is still being assembled, and that for certain populations, particularly older adults on long-term regimens, the question is live.
Proton Pump Inhibitors: The Drug Behind the Finding
Proton pump inhibitors, or PPIs, are medications commonly used to treat acid reflux and heartburn by suppressing gastric acid production. The drug class includes omeprazole, esomeprazole, pantoprazole, and lansoprazole, sold under brand names including Prilosec, Nexium, Prevacid, and Protonix. They work by blocking the enzyme in the stomach wall responsible for producing acid – reducing gastric acid output significantly and providing substantial symptom relief for conditions including GERD, peptic ulcers, and esophagitis.
PPIs reduce acid secretion in the stomach and rank as one of the most widely used acid-suppressing medicines globally. While they are considered safe in the short term, emerging evidence points to risks associated with long-term use. Those risks, in addition to the dementia association examined here, have previously included associations with chronic kidney disease, cardiovascular events, and bone fractures. The dementia link is the most recent and arguably the most alarming addition to that list.
The extended use of PPIs has been flagged as a serious health concern, as these drugs have been linked to adverse effects such as chronic kidney disease, cardiovascular disease, stroke, and dementia. That scope of potential downstream effects is a significant departure from the profile many patients were given when the medication was first prescribed to them.
It is also worth noting the sheer scale of use. PPIs are one of the most commonly used drugs worldwide. That makes even a modest elevation in dementia risk – if confirmed – a population-level concern of significant magnitude.
The Biological Mechanisms Under Investigation
How might long-term suppression of stomach acid contribute to cognitive decline? Researchers have proposed several pathways, none yet definitively proven, but all biologically plausible.
According to The Psychiatrist, possible reasons for the link include disrupted B12 absorption and alterations to gut bacteria, though more research is required before rethinking the use of these prescription drugs. The B12 pathway is mechanistically straightforward: gastric acid is required for the absorption of vitamin B12 from food, and long-term acid suppression can deplete B12 stores, which are essential to neurological function. Chronic B12 deficiency is itself an established, if underrecognized, cause of cognitive impairment.
The gut bacteria pathway is more complex and reflects growing interest in the gut-brain axis – the bidirectional communication system between the gastrointestinal microbiome and the central nervous system. Disrupting the gut environment through prolonged acid suppression may alter the microbial composition in ways that affect brain inflammation and neural signaling, though this connection remains an area of active research rather than settled science.
Study author Kamakshi Lakshminarayan stated in a media release: “While we did not find a link with short-term use, we did find a higher risk of dementia associated with long-term use of these drugs.” The researchers concluded with a call for the principle of “as needed, as short as possible.”
The Practical Neurology review of the same findings added a relevant secondary observation: secondary analysis showed no significant association between H2RA usage – an older, alternative class of acid-reducing drugs – and dementia. If the association were simply a byproduct of the underlying condition being treated (acid reflux), one would expect a similar signal from H2RAs. Its absence is noteworthy.
Who Is Most at Risk and What the Research Says About Duration
The findings place the highest concern squarely with long-term users – people who have been on the medication continuously for more than four years, which is well outside the duration guidelines set by regulatory bodies. The over-the-counter availability of PPIs means that many people extend their use far beyond any prescribed period without ongoing medical review, often because the symptoms return the moment they stop taking the drug.
For readers whose parents, partners, or older family members are taking this medication daily as a matter of habit rather than active medical necessity, the study’s framing of “cumulative years” is the relevant variable. Researchers conducted a community-based cohort study spanning from participant enrollment between 1987 and 1989 until 2017, using a visit conducted between 2011 and 2013 as the baseline for drug use, then calculated incidence of dementia after this baseline over a median follow-up of 5.5 years. The longitudinal design – tracking the same individuals over decades – makes this more robust than a snapshot observational study, even as the limitations acknowledged by the researchers remain real.
Over-the-counter versions contain the same chemical compounds as in prescription versions, just at lower doses, and the FDA recommends taking PPIs no longer than four weeks before consulting a doctor. That guidance exists, but it is not reflected in how millions of people actually use the drug.
The Prescribing Problem Hidden in Plain Sight
The dementia finding does not exist in isolation. It connects to a broader documented issue with how this class of drugs gets prescribed, continued, and never revisited. Researchers have found that many older adults with dementia or cognitive impairment are prescribed medications that can increase the risk of confusion, falls, and hospitalization. The pattern of inappropriate or overly prolonged prescribing runs across multiple drug classes – and PPIs are among the most visible examples.
Given the widespread use of PPIs and increasing concern regarding long-term use, a systematic review of global trends called for more rational prescribing – and specifically for clinicians to review PPI prescriptions regularly and deprescribe when there is no appropriate ongoing indication or evidence of benefit. “Deprescribing” – the intentional, supervised reduction or cessation of a medication no longer providing net benefit – is gaining traction as a formal clinical practice, but it is not yet standard.
The reality for many patients is that PPIs were started for a short-term problem, worked well, provided immediate and significant relief, and were never stopped. The absence of symptoms while taking the medication is taken as evidence the medication is still needed. Stopping it produces an acid rebound effect that feels like confirmation of the same logic. The cycle is self-reinforcing, and without a prescriber actively initiating a review, many patients remain on the drug indefinitely.
What to Do With This Information
The evidence from the ARIC cohort study establishes a 33 percent elevated risk of dementia in people who used this medication for more than 4.4 cumulative years – a finding significant enough to warrant serious attention, even as the broader body of evidence remains contested. The updated 2025 meta-analysis found no statistically significant risk in the pooled overall analysis, but identified a meaningful elevated risk specifically in adults aged 65 and older. These two findings are not mutually exclusive: they describe a picture in which long-term use in older populations carries genuine reason for concern, even if a universal causal link has not been established.
What is not in dispute is the prescribing context. A drug class intended for short-term use is being used long-term by a large proportion of its users, many of whom were never given a structured review of whether continuation was still warranted. The FDA’s own guidance – a maximum of four weeks of use before physician consultation – is routinely exceeded, including in the over-the-counter context where no physician is involved at all.
If someone in your life has been taking this medication every day for years without a recent conversation with their doctor about whether that’s still the right call, that conversation is now more than worth having. Not in alarm, not as a crisis, but as a straightforward question that clinical evidence has made entirely reasonable to ask. The research does not tell you to stop the drug. It tells you that “I’ve been on this for six years and nobody’s reviewed it” is no longer a sentence that should go unexamined. That is not a small thing to know.
Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.
AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.