List of dementia risk factors grows

In its most recent update, the 2024 Lancet Commission study has identified two new risk factors for dementia: untreated vision loss and high low-density lipoprotein (LDL) cholesterol.  
 
These additions mean that 45% of dementia cases could be prevented or delayed by addressing a new total of 14 risk factors starting in childhood, up from 40% of cases previously.
 
Of that 45%, LDL levels contribute to 7%, while untreated vision loss makes up 2%.
 
For GPs supporting people to reduce their dementia risk, this can be good reason to widen routine stage-of-life assessments through a ‘lens of cognitive health’.
 
That is according to Dr Marita Long, a Victorian GP with a special interest in dementia and honorary medical advisor with Dementia Australia.
 
She told newsGP the addition of more modifiable risk factors is ‘good news’.
 
‘It used to be early mid-life to late life where they had the evidence, so there’s more evidence now to address more things earlier,’ she said.
 
‘But the reality is you should be addressing them the whole way along – the old catch phrase, “never too early, never too late”.’
 
The 2024 Lancet Commission report on dementia prevention, intervention, and care builds on the last report in 2020 which added three other factors to the dementia risk timeline.
 
Vision loss had not previously been considered a risk factor, the report states, but ‘considerable new evidence’ has emerged, showing that, untreated, it is associated with a ‘pooled relative risk’ for dementia and future cognitive impairment.
 
Meanwhile, the evidence available on whether a high concentration of LDL cholesterol was a possible dementia risk factor was ‘inconclusive’ at the time of the previous Lancet Commission on dementia.
 
Since then, a meta-analysis of three cohort studies with a total of 1,138,488 adults younger than 65 years looking at LDL cholesterol, found that each 1 mmol/L increase in LDL cholesterol was associated with an 8% increase in incidence of all-cause dementia.
 
The report also details advances in fluid biomarkers for detection of Alzheimer’s disease, new definitions for diagnosis of the condition, as well as progress on disease-modifying treatments.
 
These latest findings come as the number of people living with dementia worldwide is projected to reach around 153 million by 2050.
 
In Australia, it is estimated more than 421,000 people are living with dementia in 2024, and a predicted one million people will develop the disease by 2056.
 
Dementia is the second leading cause of death of all Australians and the leading cause of death for Australian women, carrying the greatest burden of disease in people aged over 65.
 
Dr Long said the added risk factors should give GPs motivation to be looking more through the ‘lens of cognitive health’ when conducting mid-life health assessments.
 
And this is opportunistic for GPs providing preventive health and lifestyle advice which, she says, they ‘do incredibly well’.
 
‘Once upon a time, we wouldn’t have been perhaps too worried if you saw a raised LDL, if everything else looks alright,’ she said.
 
‘We might now just step back and say, “Hang on a minute, maybe this is something we should be looking at more closely”.
 
‘And it doesn’t mean you necessarily jump into prescribing medication, but you might just pay that little bit more attention to it and say, “Look, let’s look at your diet and exercise”, given that probably the biggest two risk factors for Australians are physical inactivity and obesity, and we know physical activity is really good at helping with reducing LDLs.’
 
For keeping on top of eye health, Dr Long said it is as simple as ensuring people pay attention to their eyes and get to an optometrist to have their vision corrected.
 
‘It’s not that hard to do … most optometry is Medicare rebated, but the glasses are a different thing,’ she said.

‘If [a patient’s] vision isn’t where it should be, get their eyes checked and the correct visual aid, for example, if [they] stop reading the paper because vision isn’t great, they reduce cognitive simulation and it means neural pathways aren’t being used.’
 
The Lancet report says overall, the 45% of dementia cases are potentially preventable by addressing 14 modifiable risk factors at different stages during the life course:

1. Limited education (5%, early life)
2. Hypertension (2%, mid-life)
3. Hearing loss (7%, mid-life)
4. Smoking (2%, mid-life)
5. Obesity (1%, mid-life)
6. Depression (3%, mid-life)
7. Physical inactivity (2%, mid-life)
8. Diabetes (2%, mid-life)
9. Traumatic brain injury (3%, mid-life)
10. Excessive alcohol (1%, mid-life)
11. Low social contact (5%, late life)
12. Exposure to air pollution (3%, late life)
13. Untreated vision loss (2%, late life)
14. High LDL cholesterol (7%, mid-life)

dementia dementia risk LDL cholesterol modifiable risk factors vision loss