The largest ever study on who is most likely to be at risk of developing dementia, suggested that overweight people are less prone to contracting the disease.
The study, published in the journal The Lancet Diabetes and Endocrinology, is in direct contrast to all current medical advice, which is to exercise on a regular basis, and eat a healthy diet. This is in order to reduce the BMI (body mass index).
However, the study, conducted at the London School of Hygiene and Tropical Medicines, showed that obese people, with a critically high BMI, were 30 per cent less likely to develop dementia.
For instance, a man in his 50’s who weighed 20 stone and stood at 5ft 10 would be a third less likely to develop dementia than a 10 stone man of the same height.
The results has caused confusion at the school, as all previous studies have shown that obesity raises the risk of developing dementia.
“Our results suggest that doctors, public health scientists, and policy makers need to re-think how to best identify who is at high risk of dementia,” said Professor Stuart Pocock from the Medical Statistics Unit at the London School of Hygiene & Tropical Medicine.
“It opens up an intriguing new avenue in the search for protective factors for dementia. If we can understand why people with a high BMI have a reduced risk of dementia, it’s possible that further down the line, researchers might be able to use these insights to develop new treatments.”
In the study, researchers took the medical records of just under two million people, with an average age of 55 years and a BMI which worked out on average of 26.5.
The researchers followed these people for a nine year period and discovered that around 50,000 of them developed dementia. They found however, that those who had the highest BMIs were the least likely to contract the disease.
The follow-up showed instead that people who were underweight had a greater risk of being diagnosed than people who had a normal weight. The risk lessened as people put on more weight.
Scientists already know that putting on weight in older age can help with certain disorders, such as osteoporosis, but it has never been shown to protect against developing dementia.
However, there are some medical experts that are wary of the study’s findings. They believe that misdiagnosis from a GP is more likely to be behind the results.
“Is it time to slump on the sofa, pile into the burgers and slurp the lager? Probably not just yet,” said Tom Dening, Professor of Dementia Research a the University of Nottingham.
“The ascertainment of dementia is based on a GP diagnosis of dementia. It is plausible that faced with a grossly obese patient, the average GP may have concentrated on the obvious medical risks and paid less attention to the cognitive issues than they might have done with a comparable patient of normal weight.”
And others agree that obesity is not a healthy lifestyle choice.
“While the evidence on body weight and dementia is unclear, we know that people can make positive lifestyle choices to keep their brains healthy by taking regular exercise, not smoking and following a healthy balanced diet,” said Dr Doug Brown, Director of Research and Development at Alzheimer’s Society.
Dr Liz Coulthard, Consultant Senior Lecturer in Dementia Neurology, University of Bristol, added: “We do know that obesity carries many other risks including high blood pressure, heart disease, diabetes and increased rates of some types of cancer. So maintaining a healthy weight is recommended.”
Source: The Telegraph