Study links opioid addiction to higher risk of dementia

The risk of developing dementia is 56% higher among people addicted to opioids, according to a new study.

The research – led by Oxford Population Health and the Department of Psychiatry, University of Oxford – drew upon more than 220,000 health records from the US Million Veteran Programme (MVP), a database containing the DNA and health records of more than a million retired US military service members.

These were then compared to data from a number of other large studies, including the UK Biobank, before genetic analysis was used to distinguish opioid use from other possible causes of dementia.

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The findings showed that 9,399 of the MVP participants had a diagnosis of opioid use disorder (OUD) – a condition related to the compulsive use of opioids that can develop from dependency on prescription or illicit drugs.

During follow-up of up to nine years, 8,397 of all participants developed dementia, with those diagnosed with OUD shown to be 56% more likely to develop the condition than other participants.

A strong association between OUD and Alzheimer's disease and vascular dementia was also found among participants of European heritage.

Genetic analysis showed that the impact of opioid exposure was the likely reason for the effects on the brain rather than any inherited tendency towards opioid addiction.

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Dr Anya Topiwala, senior clinical researcher at Oxford Population Health and lead author of the study – which was published in the Alzheimer's Association's journal Alzheimer's & Dementia – commented: ‘While the short-term effects of opioids are well known, our findings show that opioid use disorder may also have important long-term consequences for brain health, including a higher risk of dementia.

'Using large-scale data and genetic methods, we found evidence suggesting this link may be causal, pointing to the direct impact of opioid exposure rather than underlying genetic risk.’

While the mechanisms linking opioid addiction to dementia remain unclear, the researchers speculate that long-term opioid abuse could contribute to hardening and narrowing of the arteries, infection and hypotension, leading to a reduction to the flow of blood and oxygen to the brain.

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They also observed that dementia might have gone undiagnosed among some opioid users where the effects of their addiction clouded symptoms of cognitive decline.

‘This work underscores the need for medicine safety, preventive strategies, and further investigation into the neurological consequences of chronic opioid exposure,’ Dr Topiwala added.