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Waist measurement points to increased dementia risk

Deep abdominal fat could be major independent risk factor in damaging the brain

OnMedica Staff

Thursday, 27 March 2008

People with a large waistline by their mid 40s face a greater chance of developing dementia in later life, researchers have found. And even among men and women whose weight fell within the normal range, those with larger bellies were 89% more likely to develop dementia.

Researchers from major US health provider Kaiser Permanente in Oakland, California, suggest that excessive abdominal fat carries singular health risks and that it is an independent risk factor for dementia.

The study followed nearly 6,600 adults for an average 36 years and found that those who had a larger waist by middle age were more than three-times more likely to develop dementia. The findings were published today in the online edition of the journal Neurology

"Where you carry your weight is more important than what your weight is," the study leader, research scientist Dr Rachel Whitmer, said.

This study was not designed to answer the question of why, she said, but it's possible that there is something about deep abdominal fat that is damaging to the brain.

The study included 6,583 men and women who underwent a physical between 1964 and 1973, when they were between the ages of 40 and 45 years old. As part of that checkup, patients had a measurement of their sagittal abdominal diameter -- the span of the waist from front to back.

They then followed all of these people into their 70s to see who became ill, and who managed to maintain relatively good health.

They found the 20% of people with the largest waistlines had a 270% greater risk of dementia than those with the smallest waists.

The group with largest bellies included men and women with a sagittal abdominal diameter of roughly 9 to 16 inches. This group had a nearly three-fold greater risk of developing dementia over the next 36 years than those with the slimmest midsections in middle-age.

Some of the health problems related to abdominal obesity, including diabetes, stroke and clogged heart arteries, are associated with an increased dementia risk. But when Dr Whitmer's team factored in these conditions, belly size alone was linked to a higher dementia risk.

More research is needed to understand the reason for this, Dr Whitmer said, but there are clues from lab studies. For example, visceral fat, the fat that surrounds abdominal organs, has been shown to secrete certain hormones and inflammatory proteins that are associated with greater cognitive decline.

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