For men and women over 50, the dementia risk is 28 percent when taking body mass index and waist circumference into account together, the study researchers said.
How did they arrive at these findings?
Researchers measured participants’ height, weight and waist circumference and followed up with them an average of 11 years later to see whether they’d been diagnosed with dementia.
To isolate the link between obesity and dementia, the researchers controlled for potential confounding variables such as hypertension, diabetes, smoking and APOE ε4 gene carrier status, a known genetic risk factor for dementia.
“As belly size gets larger, the memory centre in the brain gets smaller, based on prior studies,” said Dr Richard Isaacson, who heads the Alzheimer’s Prevention Clinic at Weill Cornell Medicine and New York-Presbyterian Hospital.
“This new study is important since it supports these findings and relates a larger waist size to increased dementia risk, especially in women,” said Isaacson, who was not involved in the study.
That study’s findings could help us shed further light on the causal chain between dementia and obesity, the researchers noted.
“Dementia is one of the major health challenges of the 21st century that could threaten successful ageing of the population,” said Andrew Steptoe, a study co-author and professor of psychology and epidemiology at University College London.
He added: “Our findings suggest that rising obesity rates will compound the issue.”
The results are encouraging because they suggest people have considerable agency over their risk of developing dementia, said Steptoe.
He concluded: “By identifying factors that may raise dementia risk that are influenced by lifestyle factors, we hope that a substantial portion, but admittedly not all, of dementia cases can be prevented through public health interventions.”
What is an above average weight size?
The most widely used method to check if you’re a healthy weight is body mass index (BMI).
BMI is a measure of whether you’re a healthy weight for your height.
According to the NHS, 25 to 29.9 on the BMI measure means you’re overweight.