Large Waist Size Increases The Risk Of Dementia

A tape measureAbdominal fat is already known to be a strong risk factor for both heart disease and diabetes however a new study, published this month in the journal Neurology, has suggested that those with excess fat around the abdomen may be at almost a three times greater risk of developing Alzheimer’s disease and other dementias later in life.

6,583 middle-aged adults from the Kaiser Permanente organization in Northern California took part in the study during the 1960s and 70s which involved the measurement of individuals Sagittal Abdominal Diameter (SAD). SAD is a measurement of the thickness of the body in the middle of the point between the bottom of the ribs and the pelvic bone. It is similar to a waist circumference measurement in that it is is a measure of central or abdominal fat levels. A SAD measurement greater than 25 cm (10 inches) is considered to indicate central obesity.

By 2006, 1049 (15.9%) of the individuals in the study had been diagnosed with some form of dementia. Those with an abdominal diameter in the top 25% were at a 2.72 times greater risk of dementia compared to those in the lowest 25% of abdominal diameters. Even after adjusting for Body Mass Index (BMI) those in the highest quartile of abdominal diameters were still 92% more likely to develop dementia.

Even skinny people can be at a greater risk of dementia if they have high levels of belly fat. Those in the study who had a BMI in the healthy weight range but a abdominal diameter greater than 25cm were 89% more likely to develop dementia than those with a healthy BMI but an abdominal diameter less than 25cm.

Those in the obese BMI range (BMI greater than 30) who also had a high SAD had the highest risk of dementia with a 260% greater risk of developing dementia.

The increased risk of dementia came independent of other possible dementia risk factors such as age, education, marital status, and the presence of diseases such as heart disease, diabetes, hypertension and strokes.

Abdominal fat is predominately visceral fat. Visceral fat is known to secrete certain hormones which increase inflammation and oxidative stress in the body. Leptin, which is secreted by visceral fat cells is known to play a role in the formation of plaques in the brain. These plaques are considered to be precursors of Alzheimer’s disease.

According to lead researcher Rachel Whitmer of the Kaiser Permanente Division of Research: “Fat biologists know, that visceral fat, it is more lively, it is more toxic, it is more metabolically active. It secretes a lot of hormones and inflammatory compounds.”

Those with a large waist size are already known to be at a far greater risk of diabetes, strokes, and heart disease than those with a smaller waist size. Studies suggest that men with a waist size greater than 40 inches (102cm) are 12 times more likely to develop diabetes than those men with a waist size less than 34 inches (86cm). Another study found that women with a waist size greater than 88cm are three times more likely to develop cardiovascular disease.

The study should come as a wake up call to many people with more than fifty percent of adult Americans considered to be centrally obese.