Antimicrobials, Vaccinations, Anti-inflammatories Linked to Lower Dementia Risk

Ben Underwood, PhD

Credit: LinkedIn

A new study revealed antimicrobials, vaccination, and anti-inflammatories were associated with reduced dementia risk, whereas vitamins, supplements, and antipsychotics were associated with an increased risk.¹

Recent trials on slowing dementia progression have focused on finding safer, more effective treatments. This can be accomplished by assessing whether existing medications for other conditions affect the dementia risk.

“We urgently need new treatments to slow the progress of dementia, if not to prevent it,” said lead investigator Ben Underwood, PhD, from the department of psychiatry at the University of Cambridge and Cambridgeshire and Peterborough NHS Foundation Trust, in a statement.² “If we can find drugs that are already licensed for other conditions, then we can get them into trials and – crucially – may be able to make them available to patients much, much faster than we could do for an entirely new drug. The fact they are already available is likely to reduce cost and therefore make them more likely to be approved for use in the NHS.”

Investigators conducted a systematic review to examine 14 studies evaluating the association between a wide range of prescribed medications and dementia risk.¹ Most of the studies were conducted in the United States (n = 9), with the rest from Japan (n = 2), South Korea (n = 1), Germany (n = 1), and Wales (n = 1). Studies used administrative claims data (n = 7), electronic health records (n = 6), or both (n = 1).

The sample sizes varied from 75000 to 117 million, with a total of 139,096,622 participants. Approximately 1 million (n = 1,098,157) participants were identified with dementia, determined by ICD-9 or ICD-10 codes in the HER and claim data or in combination with prescriptions for donepezil, galantamine, rivastigmine ,or memantine.

10 studies reported associations between medications and the ≥ 50% reduced risk of dementia. Medications identified included catecholamine modulators, anticoagulants, anticonvulsants, and antibiotics/antivirals. 4 vaccines— hepatitis A, typhoid, hepatitis A and typhoid combined, diphtheria—were also identified.

Furthermore, another study identified 3 additional medications were linked to the reduced risk of Alzheimer Disease: valacyclovir (antiviral), montelukast (inflammation), and losartan (antihypertensive) (hazard ratio [HR], 0.56-0.73). A network-based study discovered other medications linked to the reduced risk of Alzheimer Disease: gemfibrozil (reduction of triglycerides), ibuprofen (anti-inflammatory), ceftriaxone (antibiotic), and cholecalciferol (vitamin D3).

The study overall discovered antimicrobials, vaccinations, and anti-inflammatories were linked to reduced dementia risk. Conversely, diabetes drugs, vitamins and supplements, and antipsychotics were associated with an increased dementia risk. Medications linked to an increased dementia risk were intended to treat conditions of cardiovascular disease, diabetes, depression, neurodegenerative diseases, dementia symptoms, dyspepsia and gastroesophageal reflux disease, nausea and vertigo, laxatives, proton pump inhibitors, hypnotics and anxiolytics, analgesics, anticonvulsants, drugs used in substance abuse, and drugs for genito-urinary disorders. However, some of these medications were also to be found with a reduced risk.

When it came to antihypertensives and antidepressants, there was conflicting evidence for how these drugs impact the dementia risk.

“Because a particular drug is associated with an altered risk of dementia, it doesn’t necessarily mean that it causes or indeed helps in dementia,” said investigator Ilianna Lourida, PhD, from the National Institute for Health and Care Research Applied Research Collaboration South West Peninsula at University of Exeter, in the press release.²

Lourida gave the example of how diabetes increases someone’s risk for dementia, so naturally, anyone on diabetes medication would be at a greater risk of dementia.

“That doesn’t mean the drug increases your risk,” Lourida continued. “It’s important to remember that all drugs have benefits and risks. You should never change your medicine without discussing this first with your doctor, and you should speak to them if you have any concerns.”

References

1. ^{Underwood, BU & Lourida, I et al. Data-driven discovery of associations between prescribed drugs and dementia risk: A systematic review. Alz & Dem; 21 Jan 2025; DOI: 10.1002/trc2.70037}
2. ^{Antibiotics, vaccinations and anti-inflammatory medication linked to reduced risk of dementia. EurekAlert! January 21, 2025. https://www.eurekalert.org/news-releases/1070702. Accessed January 20, 2025.}