Obesity increases the risk of dementia

Swedish researchers discover the link between obesity and dementia

04/05/2011

Overweight in middle age increases the risk of dementia in old age by 80 percent. This is the finding of Swedish researchers from the Karolinska Institute in Stockholm as part of a comprehensive study of 8,534 twins aged 65 and over.

The risk of dementia is 80 percent higher in middle-aged people with a body mass index (BMI) of more than 25 percent, according to researchers from the Karolinska Institute in the journal „Neurology“. The scientists found a clear correlation between overweight in middle age and dementia later in life when evaluating data from a Swedish twin registry maintained for more than four decades.

Association between dementia and obesity is examined
In the context of their study, the Swedish researchers examined the current health status of the 8,534 twins aged 65 and over with regard to possible dementia and then compared this with the BMI of middle-aged subjects. The scientists were able to deduce the BMI from the data of the Swedish twin registry on the size and weight of the subjects 30 years ago. The researchers of the Karolinska Institute found out in a first step that 350 study participants suffered from an already diagnosed dementia, 114 had symptoms for a reasonable suspicion. In determining the BMI the subjects had in middle age, the researchers concluded that 2,541 of the 8,534 twins in middle age were overweight or obese.

Overweight in middle age dramatically increases the risk of dementia
In analyzing possible associations between dementia and overweight subjects, the Karolinska Institute researchers found that those with dementia had a much greater share of obesity in their early life than healthy subjects. According to the researchers, 36 percent of subjects with suspected dementia were overweight, and five percent were obese. In the study participants with already existing dementia diagnosis, the proportion of obese was even 39 percent, obese were seven percent. In contrast, only 26 percent of subjects without dementia were overweight in their middle age and three percent were obese. From this, the researchers derive an 80 percent increased risk of dementia later in life in overweight in the middle years of life. The correlation between obesity and dementia risk has also been confirmed when other factors such as educational attainment, genetic predisposition, diabetes or vascular disease are taken into account, the researchers report.

Connection between diet and brain diseases
The Swedish researchers confirm with their study the results of previous studies, which already suggested a connection between brain diseases and increased body weight. For example, Antonio Convit from the Nathan Kline Institute for Psychiatry Research in New York and colleagues reported in early January in the journal „Brain“, that in obese people a clear reduction of certain reward and appetite centers in the cerebrum as well as considerable structural damage of the brain can be detected. Their study suggests that the already known from earlier studies proinflammatory effect of the excess weight in the nervous system, entire brain areas can shrink, wrote the US researchers earlier this year. The results of the current Swedish study point in a similar direction and underline the importance of a healthy diet for health in old age. (Fp)

Also read:
Dementia and Alzheimer's
Dementia: holistic treatment approach
Alzheimer's discernible years before the outbreak
World Alzheimer's Day: Experts warn against dementia

Picture: Gerd Altmann