POOR education, hearing loss and smoking have been singled out as the main, preventable risk factors for dementia, by the scientist leading a new study.

Alzheimer’s Disease International (ADI) worked with the Lancet Commission to develop 12 evidence-based factors which could prevent or delay 40 per cent of all dementias if they were removed.

Of those, hearing impairment, low education and smoking accounted for half of those cases.

Overall, a growing body of evidence supports nine potentially modifiable risk factors for dementia, which also include high blood pressure, obesity, depression, physical inactivity, diabetes, and low social contact. 

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Researchers said they can now add three more which have newer, convincing evidence; alcohol consumption, traumatic brain injury, and air pollution.

Professor Gill Livingston, of University College London, who was involved in the report – Dementia prevention, intervention and care – warned about a rise in “clickbait medicine” media headlines suggesting individual foods or vitamins could prevent the disease.

HeraldScotland:

She said:  “It sometimes seems like some the media in the world want to label everything in the world as either preventing or causing dementia.

“The evidence is that taking individual vitamins does not help dementia, there are quite a lot of studies and it really does not seem to make any difference at all.

"I think that’s really important because they are sold to people as something that will really make a difference.

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“While I don’t think they are going to do any harm – they are probably not eating them in sufficient doses –but they don’t  make any difference either. What we did was look at the amount of dementia that could be removed if the risk factor disappeared.

“The three that account for most are hearing impairment, followed by low education levels, followed by cigarette smoking. These 12 risk factors make up 40% of all the risk of all dementia but those three make up 20%, so half.

“We have very good evidence about all those 12 things. There are other things we have suspicions could help but we don’t have the weight of as much evidence.

“In general, people who eat a Mediterranean diet do better, so lots of fruit and vegetables and fish and not much meat and butter but that’s mixed up in the fact they can afford to eat a Mediterranean diet.”

Professor Livingston, who is originally from Glasgow, said Scotland was ahead of England in recognising the risks of children heading footballs. The SFA (Scottish Football Association)  introduced a headers ban for children under 12 in February. 

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It followed a study by the University of Glasgow which found ex-footballers are approximately three and a half times more likely to die from neurodegenerative disease than the general population,

She said: “The SFA is ahead of everyone else but I think they should consider making it a bit older than under 12.

“There’s been a lot of talk about rugby over the past few days. I don’t think there is any doubt that head injury causes an excess of dementia.

“It makes sense that heading a ball, which is a really big thing for a kid, might increase the risk of head injuries but it’s very difficult to find the evidence for that because people don’t come to casualty.

“Playing rugby and other games is absolutely good. It helps in terms of dementia but we should not allow children to head footballs.”

The report calls on governments to prioritise childhood education for all and says decreasing harmful alcohol drinking could potentially reduce young-onset and later-life dementia while the use of hearing aids could ameliorate the risks .

Researchers said passive smoking is a less considered modifiable risk factor  and say improvements in air quality, particularly in areas with high air pollution, should be prioritised.