For older adults, your current belly size could be a key indicator in whether you develop dementia within the next decade or two. For women that risk is particularly high.

For women in later adulthood, above average belly fat can lead to a 39% increased risk of dementia within 15 years compared with those who have a normal waist circumference, according to a study published Tuesday in the International Journal of Epidemiology.

For men and women over 50, the dementia risk is 28% when taking body mass index and waist circumference into account together, the study said.

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.

“As belly size gets larger, the memory center 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 unravel more about 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 aging of the population,” said Andrew Steptoe, a study co-author and professor of psychology and epidemiology at University College London.

“Our findings suggest that rising obesity rates will compound the issue.”

Medical reference: CNN Health