Want to reduce your risk of dementia?

Two separate studies released in recent weeks have offered new insights into risk factors for dementia, and how to counter them.

The bad news is that regular use of certain types of commonly prescribed drugs used to treat bladder conditions, Parkinson’s disease and depression appear to significantly increase the risk of dementia in later life. The study was led by the University of Nottingham and published in JAMA Internal Medicine.

Anticholinergic drugs help to contract and relax muscles, and work by blocking acetylcholine — a chemical that transmits messages in the nervous system. These medicines can have short-term side effects, including confusion and memory loss, but it is less certain whether long-term use increases the risk of dementia.

Now, researchers have looked at the medical records of 58,769 patients with a diagnosis of dementia and 225,574 patients without a diagnosis of dementia, all aged 55 and over and registered with UK GPs contributing data to the QResearch database, between 1 January 2004 and 31 January 2016. They found that there was nearly a 50% increased risk of dementia among patients aged 55 and over who had used strong anticholinergic medication daily for three years or more.

The study findings showed increased risks of dementia for anticholinergic drugs overall and specifically for the anticholinergic antidepressants, antipsychotic drugs, antiparkinsons drugs, bladder drugs and epilepsy drugs after accounting for other risk factors for dementia. No increased risks were found for the other types of anticholinergic drug studied, such as antihistamines and gastrointestinal drugs.

The researchers note that this is an observational study so no firm conclusions can be drawn about whether these anticholinergic drugs cause dementia, and it is possible that the drugs were being prescribed for very early symptoms of dementia. They do, however, suggest that doctors should be careful when prescribing certain drugs that have anticholinergic properties, and that concerned patients should discuss the pros and cons of their any treatment with their doctor.

“The risks of this type of medication should be carefully considered by healthcare professionals alongside the benefits when the drugs are prescribed and alternative treatments should be considered where possible, such as other types of antidepressants or alternative types of treatment for bladder conditions,” said Professor Carol Coupland, who led the study.

“We found a greater risk for people diagnosed with dementia before the age of 80, which indicates that anticholinergic drugs should be prescribed with caution in middle-aged people as well as in older people.”

These results, along with those of a similar study published in 2018, help to clarify which types of anticholinergic drug are associated with the highest risks of dementia. Further research is now needed to confirm whether or not the association between these drugs and risk of dementia is causal.

The good news is that a healthy lifestyle can decrease risk of dementia — even when that risk is genetic — according to new research from the University of Exeter, the University of South Australia (UniSA), the University of Michigan and the University of Oxford.

Published in JAMA, the study saw researchers analyse data from 196,383 adults of European ancestry aged 60 and older from UK Biobank and identify 1769 cases of dementia over a follow-up period of eight years. The team grouped the participants into those with high, intermediate and low genetic risk for dementia, with each genetic risk factor weighted according to the strength of its association with Alzheimer’s disease. To assess lifestyle, researchers grouped participants into favourable, intermediate and unfavourable categories based on their self-reported diet, physical activity, smoking and alcohol consumption.

The research found the risk of dementia was 32% lower in people with a high genetic risk if they had followed a healthy lifestyle, compared to those with an unhealthy lifestyle. Meanwhile, participants with high genetic risk and an unfavourable lifestyle were almost three times more likely to develop dementia compared to those with a low genetic risk and favourable lifestyle.

“This is the first study to analyse the extent to which you may offset your genetic risk of dementia by living a healthy lifestyle,” said Dr Elżbieta Kuźma, from the University of Exeter Medical School. “Our findings are exciting as they show we can take action to try to counteract our genetic risk for dementia. Sticking to a healthy lifestyle was associated with a reduced risk of dementia, regardless of the genetic risk.”

Professor Elina Hyppönen, Director of UniSA’s Australian Centre for Precision Health, said she anticipates that UniSA will be involved in related research in future — as will Australia’s National Health and Medical Research Council (NHMRC), which partially funded the study. In fact, UniSA has since been awarded more than $1.2 million from the NHMRC to uncover the aspects of diet and activity that make up a kind of ‘best practice day’ for people who want to reduce their risk of dementia.

Dr Ashleigh Smith, lead researcher for the new project, said while there is a plethora of research looking at how individual lifestyle factors can mitigate the chances of getting dementia, knowing how factors work together to optimise dementia prevention is increasingly important. The ultimate goal of the study, she said, is to develop an evidence-based tool that people can use to target improvements in diet and activity, designed to underpin better brain health.

“We are aiming to develop an easy-to-use app that will help people adjust their activities — give them the opportunity to choose to sleep a little longer, walk a little more often, spend less time on passive activities or switch out less nutritious foods for options from a healthy Mediterranean diet,” she said.

The research project will focus on diet and activity and will examine longitudinal data from a cohort of 450 people aged between 60 to 70 years over three years. It will be undertaken across four Australian universities and feature experts in the use of time epidemiology, cognitive assessment, diet, cerebrovascular assessment, neuroimaging and non-invasive brain stimulation.

Image credit: ©stock.adobe.com/au/Monkey Business Images