Having a large gut in midlife increases the chance of dementia in old age, according to new research published Wednesday that suggests that abdominal fat is a bigger risk factor than even family history.
The study of 6,583 adults found that people with the highest amount of abdominal fat between the ages of 40 and 45 were about three times more likely to develop dementia than those with the lowest amount.
By contrast, people who have parents or a sibling with Alzheimer's face twice the risk of developing the disease.
The report in the journal Neurology was the latest to show that belly fat can pose serious health risks, even for those who are not obese. Previous research has shown that people with large abdomens face a greater chance of diabetes, stroke and heart disease.
"This ought to be a wake-up call to baby boomers in terms of diet and exercise," said Dr. Sam Gandy, a spokesman for the Alzheimer's Assn. who was not involved in the study. "If they are not frightened enough about heart disease, maybe they will worry about losing their mental function."
Dementia is an age-related condition that involves the loss of memory and other cognitive functions. It affects 5.7 million Americans, or about 1 in 10 people over age 65. Alzheimer's is the most common form of dementia, accounting for 60% to 80% of cases.
Being overweight has also become a significant health problem in the U.S. About 50% of the nation's adults have an unhealthy amount of belly fat, according to the latest report.
People who tend to pack on abdominal fat are often described as apple-shaped and have a waist-to-hip ratio greater than 1 to 1 if they are male and greater than 0.8 to 1 if they are female.
The other major overweight group has a body type described as pear-shaped, characterized by fat around the thighs and lower body.
Participants in the study were members of Kaiser Permanente of Northern California who had their belly fat measured between 1964 and 1973.
Clinicians measured belly fat by placing one end of a tong-like instrument on the back of each subject and the other end of the tong on the subject's abdomen. A person had high belly fat if the distance between the two ends -- the subject's diameter -- was more than 25 centimeters, or 9.8 inches.
An average of 36 years later, 16% of the participants had been diagnosed with dementia.
