Dementia risk linked to some medicines

A study links the long-term use of some drugs with a higher risk of dementia.

In England, 1.5 to two million people are likely to be taking anticholinergics for depression, Parkinson’s and bladder problems.

University of East Anglia researchers found more cases of dementia in patients prescribed larger quantities of particular anticholinergics.

But experts said patients should not stop taking them, as their benefits may outweigh any risk.

The study found no risk with other anticholinergic medicines used to treat common conditions such as hay fever, travel sickness and stomach cramps.

What did the study look at?

The research, funded by Alzheimer’s Society and published in the British Medical Journal, looked at the medical records of 40,770 patients aged from 65 to 99 with a diagnosis of dementia between April 2006 and July 2015 and compared them with those of 283,933 people without dementia.

It also analysed more than 27 million prescriptions – making it the biggest study of its kind into the long-term impact of anticholinergic drugs in relation to dementia.

What are anticholinergic drugs?

They block acetylcholine, a chemical messenger that carries signals across the nervous system.

Some are available on prescription only.

What should patients do if they take any of these drugs?

The most important thing is “not to panic”, according to Dr Ian Maidment, from Aston University.

“Don’t do anything suddenly. Don’t stop taking your medication,” he told the BBC.

“As a patient, if you are concerned about it, go and speak to your doctor or your pharmacist. You don’t have to see them urgently.”

Not taking prescribed drugs could have serious consequences, Dr Maidment said.

“Having untreated depression is also a risk as people can die from that, so it is a question of balancing risks,” he added.

How have experts reacted?

Alzheimer’s Society head of research Dr James Pickett told the BBC that compared with the risk of dementia being caused by an unhealthy lifestyle, the potential risk of an anticholinergic drug contributing to the onset of the disease was “quite small”.

“We don’t exactly know within those that are taking these drugs, who is at the increased risk and who isn’t,” he said.

Dementia Research national director Prof Martin Rossor said: “It is important to be cautious about associations as they do not prove causation.”

Alzheimer’s Research UK research director Dr Carol Routledge said: “The study didn’t investigate what might cause this link between anticholinergics and dementia risk, and researchers will need to build on these findings in future studies.”

Rob Howard, professor of old age psychiatry at University College London, said: “It is possible that use of some of these drugs may have actually been to treat the very earliest symptoms of Alzheimer’s disease, which can be associated with low mood and lower urinary tract infections, many years before the development of dementia.”

Dr Parastou Donyai, associate professor of social and cognitive pharmacy at the University of Reading, said: “This type of study imagines that patients actually take their drugs as they were prescribed for them.

“But we know from other research that people with long-term health conditions really only take their medication as prescribed around half of the time – the other half, people either take more or less of their medication or not at all.”

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Brain injuries increase dementia risk, study finds

People who suffer brain injuries are at increased risk of dementia later in life, a large study suggests.

An analysis of 2.8 million people found those who had one or more traumatic brain injuries were 24% more likely to get dementia than those who had not.

The risk was greatest in people who had the injuries in their 20s, who were 63% more likely to get the condition at some point in their life.

But independent experts said other lifestyle factors were more important.

  • Alzheimer’s researchers win brain prize

    Dementia, a category of brain diseases that includes Alzheimer’s, affects some 47 million people worldwide – a number expected to double in the next 20 years.

    Previous research has suggested a link between brain injuries – leading causes of which include falls, motor vehicle accidents, and assaults – and subsequent dementia, but evidence has been mixed.

    This new study, which followed people in Denmark over a 36-year period, found those who had experienced even one mild TBI (concussion) were 17% more likely to get dementia, with the risk increasing with the number of TBIs and the severity of injury.

    Sustaining the injury at a younger age appeared to further increase the risk of getting the condition, the research found.

    Those who suffered a TBI in their 30s were 37% more likely to develop dementia later in life, while those who had the injury in their 50s were only 2% more likely to get the condition.

    Jesse Fann, professor of psychiatry and behavioural sciences at the University of Washington School of Medicine in Seattle, said: “Our analysis raises some very important issues, in particular that efforts to prevent traumatic brain injury, especially in younger people, may be inadequate considering the huge and growing burden of dementia and the prevalence of TBI worldwide.”

    But Prof Fann explained that the actual risk of getting dementia after a brain injury was small, as less than 5% of the people in the study ended up getting the condition and of those, about 5% had suffered a TBI.

    The study, published in the Lancet Psychiatry, focused on brain injuries that were treated in hospital but the data did not break down what the causes were.

    Prof Fann added: “Our findings do not suggest that everyone who suffers a traumatic brain injury will go on to develop dementia in later life.”

    While the paper did not specifically look at brain injuries caused through sport, Dr Mahmoud Maina, research fellow at the University of Sussex, said the study “reinforces the fact that sports in which head injury occurs are dangerous and may make us susceptible to dementia”.

    Professor Tara Spires-Jones, from the University of Edinburgh, said the study “strongly supports the conclusion that TBI is associated with increased risk of dementia”.

    But Dr Doug Brown, chief policy and research officer at Alzheimer’s Society, said brain injuries were a “much smaller” contributory factor than smoking or a sedentary lifestyle – “risk factors that are much easier for all of us to do something about”.

    Dr Carol Routledge, director of research at Alzheimer’s Research UK, added that a healthy diet, drinking in moderation and not smoking were all things that can help maintain a healthy brain as we age.

    Prof Fann said the study was limited by the fact it was taken from one country with a largely similar ethnic population, so the findings cannot be generalised to all ethnic groups in other countries.

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Dementia ‘linked’ to common over-the-counter drugs

A study has linked commonly used medicines, including over-the-counter treatments for conditions such as insomnia and hay-fever, to dementia.

All of the types of medication in question are drugs that have an “anticholinergic” effect.

Experts say people should not panic or stop taking their medicines.

In the US study in the journal JAMA Internal Medicine, higher doses and prolonged use were linked to higher dementia risk in elderly people.

The researchers only looked at older people and found the increased risk appeared when people took drugs every day for three years or more.

Side-effects

All medicines can have side-effects and anticholinergic-type drugs that block a neurotransmitter called acetylcholine are no exception.

Patient information leaflets accompanying such drugs warn of the possibility of reduced attention span and memory problems as well as a dry mouth.

But researchers say people should also be aware that they may be linked to a higher risk of developing dementia.

Dr Shelly Gray and colleagues from the University of Washington followed the health of 3,434 people aged 65 and older who had no signs of dementia at the start of the study.

They looked at medical and pharmacy records to determine how many of the people had been given a drug with an anticholinergic effect, at what dose and how often and compared this data with subsequent dementia diagnoses over the next decade.


Drugs in the study

The US study does not name specific brands, but does outline the types of treatments investigated, which include:

  • Tricyclic antidepressants for treating depression
  • Antihistamines used to treat hay-fever and allergies
  • Antimuscarinics for treating urinary incontinence

    Most of the drugs were given on prescription, rather than bought at the pharmacy over-the-counter.


    The most commonly used anticholinergic-type drugs were medicines for treating depression, antihistamines for allergies such as hay-fever or to aid sleep/promote drowsiness, and drugs to treat urinary incontinence. Nearly a fifth were drugs that had been bought over the counter.

    Over the course of the study, 797 of the participants developed dementia.

    ‘Not causal’

    The study estimated that people taking at least 10 mg/day of doxepin (antidepressant), four mg/day of diphenhydramine (a sleep aid), or five mg/day of oxybutynin (a urinary incontinence drug) for more than three years would be at greater risk of developing dementia.

    The researchers say doctors and pharmacists might want to take a precautionary approach and offer different treatments instead. And when there is no alternative, they could give the lowest dose for the shortest time possible.

    Dr Gray says some of the study participants have agreed to have an autopsy after their death.

    “We will look at the brain pathology and see if we can find a biological mechanism that might explain our results.”

    Dr Simon Ridley, head of research at Alzheimer’s Research UK, said the study was interesting but not definitive – there was, he said, no evidence that these drugs cause dementia.

    Dr Doug Brown, from the UK’s Alzheimer’s Society, said: “There have been concerns that regular use by older people of certain medications with anticholinergic effects, such as sleep aids and hay-fever treatments, can increase the risk of dementia in certain circumstances, which this study supports.

    “However, it is still unclear whether this is the case and if so, whether the effects seen are a result of long-term use or several episodes of short-term use. More robust research is needed to understand what the potential dangers are, and if some drugs are more likely to have this effect than others.

    “We would encourage doctors and pharmacists to be aware of this potential link and would advise anyone concerned about this to speak to their GP before stopping any medication.”

    He said the charity was funding more research in this area to better understand any connections between these and other drugs on the development of dementia.

    The Medicines and Healthcare Products Regulatory Agency, which monitors the safety of medicines in clinical use in the UK, said it would review any new evidence.

    Drug company Johnson & Johnson Ltd said many hay-fever products sold in the UK now contain newer, second generation antihistamines – not the type looked at in the study.

    Matthew Speers, who represents the UK trade association for manufacturers of over-the-counter drugs, said: “Over-the-counter allergy and sleeping aid products are not intended to be used continuously and people are advised to talk to their pharmacist or doctor if they need to use these products long-term.

    “There are a range of allergy products on the market which contain a number of different ingredients, many of which were not considered in this study.”