Being Overweight Linked to Lower Dementia Risk
For those of us stuck in the seemingly endless battle of trying to lose weight, there might be some good news that doesn’t involve dieting! Research from Spain and the UK suggests that overweight people have a smaller chance of developing dementia when they get older than those who are underweight.
Dementia has been one of the conditions at the forefront of medical studies for some time now – we’ve even covered quite a few promising stories on the subject. But it is thought that the number of dementia patients worldwide could treble to 135 million by the 2050, and there isn’t currently any cure of treatment for the condition.
Dementia charities advise a balanced diet, exercising, and not smoking – generally maintaining a healthy lifestyle. But what more could be done?
There have been many previous studies proposing that obesity is likely to lead to dementia in old age. Because of this, Oxon Epidemiology in Spain and the London School of Hygiene and Tropical Medicine (LSHTM) decided to investigate the possible association between BMI and the risk of dementia.
The team carried out a retrospective study, which means they analysed medical records from a set time in the past, in this case from 1992 to 2007, looking for any correlation in the matter.
Almost two million people during that time frame, who were 40 or older, had their BMI (Body Mass Index) recorded. The patients were then observed until they either developed dementia, died, or transferred to another practice where they were no longer followed-up.
The study is considered one of the largest and most precise investigations into the relationship between BMI and dementia, and has been published in The Lancet Diabetes & Endocrinology.
One of the least surprising indications was that underweight people in the study appears to have a 39% greater chance of developing dementia than those who maintained a healthy weight.
The shocking finds came from looking at the results of overweight and obese people – there appeared to be a reduction in dementia cases, 18% and 24% respectively.
“Yes this is a surprise,” said lead research Dr Nawab Qizilbash. He described the results as a controversial observation, and contrary to most, if not all, other studies on the subject. “But if you collect them all together, our study overwhelms them in terms of size and precision.”
The team, however, has only been able to speculate as to what could be happening inside people carrying a little more weight than others. One theory works on the theory that being deficient in vitamins D and E could contribute to dementia, and these deficiencies might be less common in people who eat more food, and therefore vitamins.
Dr Stuart Pocock is a professor of medical statistics and one of the authors of the paper. He explained that when it comes to obesity, people just see it as a bad state to be in, in general, probably because it is linked to so many health problems. “But dementia isn’t one of them,” he proposed. “That is new information that people need to take on board.”
As the results are tentative and observational, the team points out that they shouldn’t be used as an excuse to eat more or unhealthily. Health complications such as heart disease, diabetes, and some cancers, to name but a few, have all been linked to obesity, which is a healthy lifestyle is always advocated.
“You can’t walk away and think it’s okay to be overweight or obese,” explained Dr Qizilibash. “Even if there is a protective effect, you may not live long enough to get the benefits.”
Because dementia and its possible factors can become a controversial subject, the team wants to make it clear that being overweight doesn’t automatically reduce your risk of developing dementia in your old age.
The team’s interpretation of the results is that being underweight for twenty or so years through middle age to old age increases a person’s risk of dementia. However, this doesn’t mean that obesity in middle age reduces the risk of dementia later on, just that being overweight and obese does not increase the risk as previously believed.
“These new findings are interesting, as they appear to contradict previous studies linking obesity to dementia risk,” said Alzheimer’s Research UK Head of Research, Dr Simon Ridley, commenting on the findings. “The results raise questions about the links between weight and dementia risk. Clearly, further research is needed to understand this fully.”