Dementia risk of putting on (or losing) weight too quickly

RAPIDLY gaining – or losing – weight in your 60s or 70s significantly increases the risk of dementia, a major study has found.

A body mass index change of more than 10 per cent in two years made the illness more common over the next five.

Researchers suspect that rapid weight change affects hormone balances – particularly insulin levels that can disrupt the operation of critical brain cells.

they also said the functioning of blood vessels – especially when lots of fat is quickly piled on – can be affected, reducing bloodflow to the brain.

It had been assumed for decades that illnesses such as Alzheimer’s were a part of getting older, depending on your genes.

But while DNA does play a role, increasing evidence suggests that lifestyle, weight and diet make a huge difference. Around a third of dementia cases are now thought to be influenced by such factors. the researchers in the latest study, who are based at Daegu University in South Korea, tracked 67,000 patients aged 60 to 79. ‘Both weight gain and weight loss may be significant risk factors associated with dementia,’ they wrote in the BMJ Open medical journal. ‘Our results suggest that continuous weight control, disease management and the maintenance of a healthy lifestyle are beneficial in the prevention of dementia, even in later life.’

they found that a 5ft 4in woman weighing 11st 6lb would increase her chance of dementia by about 17 per cent if she lost or gained more than 1st 1lb in two years.

For a man of 5ft 9in and 12st 12lb, a 1st 6lb weight change would see his risk go up by roughly 25 per cent. Last week the World Health Organisation published its first guidelines on dementia saying: ‘It is not a natural or inevitable consequence of ageing.

‘ Several recent studies have shown a relationship between the development of cognitive impairment and dementia with lifestylerelated risk factors, such as physical inactivity, tobacco use, unhealthy diets and harmful use of alcohol.’

James Pickett, head of research at the Alzheimer’s Society, said understanding lifestyle factors was crucial to potentially stopping patients developing the condition.

But he said the Korean study was complicated by the fact that dementia patients often lose their appetite in the early stages of the disease – so those losing weight may have dementia already.

‘ It’s difficult to distinguish between cause and effect,’ Dr Pickett said. ‘People with early dementia can often report changes in appetite and diet.

‘this study did confirm heart disease and diabetes are risk factors. While our research continues, regular exercise, eating healthy food and avoiding smoking and too much alcohol are all lifestyle habits which will not only help maintain a healthy weight, but will also be good for your brain.’

Around 850,000 Britons are estimated to have dementia.