Study links Obesity to Alzheimer's Disease

In a study published in May’s issue of Neurology, researchers reported that people who are obese during middle age suffer a heightened risk of developing dementia or Alzheimer’s disease.

Those who fall into the category of overweight and middle aged, according to researchers, have an 80% higher of developing Alzheimer’s or dementia than non-obese middle-aged people.

"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,” wrote Dr. Weili Xu, conductor of the research at the Karolinska Institute in Stockholm.

Xu and colleagues at the institute collected data from participants as well factored in information from records of their participants dating back three decades prior to the commencement of the study. The data gathered included the body weight, age, and height of each individual from three decades earlier.

The study included 8,534 participants ages sixty-five and older.

Obese individuals are classified as those with Body Mass Index (BMI) greater than 30; overweight individuals are classified as having a BMI between 25 and 30. A BMI between 20 and 25 is classified as normal.

2,541 participants of the study (almost 30%) had either been overweight or obese between ages forty and sixty, and 350 (75%) of these overweight individuals went on to develop dementia and 114 with possible dementia. Only 3% of healthy seniors had been obese during middle age.

Further, the researchers found that those who had been overweight in middle age suffered a 1.8 times (80%) higher risk of being diagnosed with dementia later in life. Those who had been obese in middle age, classified as possessing a BMI of 30 or above, had an almost four times (300%) higher risk of developing dementia.

This possible future of overweight individuals is highly concerning, as obesity has become a bit of an epidemic in North America, as well as parts of Europe. According to the Alzheimer's Society, around 750,000 individuals in the United Kingdom suffer from dementia, and more than half of this number lives with Alzheimer's. With this new research, it is predicted that by 2021 one million people in the UK alone will be living with dementia.

It is not certain how excess body weight can impact the deterioration of the human brain, but Xu stated that there are many possible mechanisms that could possibly be at play. "Higher body fat is associated with diabetes and vascular diseases, which are related to dementia risk," she said.

Xu stressed the need for healthy living at all junctures of life, especially middle age; she also added that there were other factors accounted for in the data that could affect a person’s weight, such as education. "Based on this data, every one year in higher education is associated with about 10% reduced risk of overweight and obesity, and 8% decreased risk of dementia."