If you are obese or overweight and middle aged, your risk of subsequently developing dementia, Alzheimer’s disease or vascular dementia is significantly higher, compared to other people of your age of normal weight, researchers from the Karolinska Institute reported in journal Neurology. With such a large percentage of North America’s and Europe’s adult population being overweight, the authors wonder what the dementia rate is going to be like in a couple of decades’ time.

Study author, Weili Xu, MD, PhD., said:

“Currently, 1.6 billion adults are overweight or obese worldwide and over 50% of adults in the United States and Europe fit into this category.”

Xu and team gathered data from the Swedish Twin Registry, which included 8,534 twins aged at least 65. Three-hundred and fifty of them had been diagnosed with dementia and a further 114 with possible dementia. Their body weight and height details 3 decades earlier were also included in the data.

The researchers grouped the individuals according to their Body Mass Index (BMI), into:

  • obese – BMI over 30
  • overweight – BMI between 25 and 30
  • normal weight – BMI between 18 and 25
  • underweight – BMI under 18

30% of the twins (2,541) had been overweight/obese during middle age.

Their findings showed that the individuals who had been overweight/obese during middle age were 80% more likely to develop dementia, Alzheimer’s disease or vascular dementia during old age, compared to the normal weight participants. The risk difference was calculated after taking into account such factors as diabetes status, vascular disease and education.

26% of the elderly individuals who had been overweight during middle age had no dementia, compared to 36% with possible dementia and 39% of those definitely diagnosed with dementia.

3% of the healthy seniors had been obese during middle aged, compared to 7% of those who were diagnosed with dementia and 5% of patients with possible dementia.

They also looked into whether there might be any difference between twin pairs who had varying bodyweights during middle age. Here they found no significant correlation between overweight/obesity and dementia.

Xu said:

“This suggests that early life environmental factors and genetic factors may contribute to the link between midlife overweight and dementia.”

“Midlife overweight and obesity increase late-life dementia risk – A population-based twin study”
W.L. Xu, MD, PhD, A.R. Atti, MD, PhD, M. Gatz, PhD, N.L. Pedersen, PhD, B. Johansson, PhD and L. Fratiglioni, MD, PhD
Neurology May 3, 2011 vol. 76 no. 18 1568-1574

Written by Christian Nordqvist