May 07, 2008
Obesity Boosts Dementia Risk

Being too skinny also poses a dementia risk?

Being obese can increase the risk of Alzheimer’s Disease by as much as 80 per cent, according to a study in the May issue of Obesity Reviews.

It is harder to tease out harmful effects of low weight as compared to overweight because people who have undiagnosed diseases often lose weight before getting diagnosed. So the population of skinny people include people who are about to get diagnosed with cancer or some other disease. The longer a group gets followed the less that bias influences the results.

But it’s not just weight gain that poses a risk. People who are underweight also have an elevated risk of dementia, unlike people who are normal weight or overweight.

US researchers carried out a detailed review of 10 international studies published since 1995, covering just over 37,000 people, including 2,534 with various forms of dementia. Subjects were aged between 40 and 80 years when the studies started, with follow-up periods ranging from three to 36 years.

The review, which included studies from the USA, France, Finland, Sweden and Japan, also included a sophisticated meta-analysis of seven of the studies, published between 2003 and 2007 with a follow-up period of at least five years.

All kinds of dementia were included, with specific reference to Alzheimer’s Disease and to vascular dementia – where areas of the brain stop functioning because the blood vessels that supply them are damaged by conditions such as high blood pressure or heart disease.

“Our meta-analysis showed that obesity increased the relative risk of dementia, for both sexes, by an average of 42 per cent when compared with normal weight” says Dr Youfa Wang, Associate Professor of International Health and Epidemiology at Johns Hopkins Bloomberg School of Public Health, Baltimore.

“And being underweight increased the risk by 36 per cent.

“But when we looked specifically at Alzheimer’s Disease, the increased risk posed by obesity was 80 per cent. The increased risk for people with vascular dementia was 73 per cent.

The harmful effects of obesity suggest that bariatric surgery ought to be considered by the chronically obese. Here's another reason: bariatric surgery might cure type 2 insulin resistant diabetes.

Share |      Randall Parker, 2008 May 07 11:19 PM  Aging Diet Brain Studies

Bob Badour said at May 8, 2008 6:16 AM:

1 In 50 People Die Within A Month Of Surgery

There are other methods of losing weight and ending type II diabetes that don't have quite the same risk of imminent death. A ketogenic diet under a doctor's supervision, for example. Recommending something with a 2% risk of immediate death seems irresponsible.

Randall Parker said at May 9, 2008 7:01 PM:


1) Very few people take off weight and keep off weight even when faced with high risks from remaining oveweight. People with high blood pressure, insulin resistant diabetes, heart problems, sleep apnea, and other high risk disorders remain overweight.

2) Weight loss does not always end insulin resistant diabetes.

3) Some people who are skinny have insulin resistant diabetes.

Bob Badour said at May 10, 2008 6:19 PM:

Full remission in 65% and partial remission in 12% suggests to me the surgery is no better than a ketogenic diet.

What's probably more important: If they ever demonstrate a mechanism of efficacy, that might lead to equally effective treatments that do not involve dangerous surgery.

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