Big belly boosts risk of later dementia
NEW YORK—Having a big belly in your 40s
can boost your risk of getting Alzheimer's disease or other dementia
decades later, a new study suggests.
It's
not just about your weight. While previous research has found evidence
that obesity in middle age raises the chances of developing dementia
later, the new work found a separate risk from storing a lot of fat in
the abdomen. Even people who weren't overweight were susceptible.
That
abdominal fat, sometimes described as making people apple-shaped rather
than pear-shaped, has already been linked to higher risk of developing
diabetes, stroke and heart disease.
"Now we can add dementia to
that," said study author Rachel Whitmer of the Kaiser Permanente
Division of Research in Oakland, Calif.
She and others report the findings in Wednesday's online issue of the journal Neurology.
The
study involved 6,583 men and women who were ages 40 to 45 when they had
checkups between 1964 and 1973. As part of the exam, their belly size
was measured by using a caliper to find the distance between their
backs and the surface of their upper abdomens. For the study, a
distance of about 10 inches or more was considered high.
The
researchers checked medical records to see who had developed
Alzheimer's or another form of dementia by an average of 36 years
later. At that point the participants were ages 73 to 87. There were
1,049 cases.
Analysis found that compared to people in the study with normal body weight and a low belly measurement:
-- Participants with normal body weight and high belly measurements were 89 percent more likely to have dementia.
--
Overweight people were 82 percent more likely if they had a low belly
measurement, but more than twice as likely if they had a high belly
measurement.
-- Obese people were 81 percent more likely if they
had a low belly measurement, but more than three times as likely if
they had a high measurement.
Whitmer said there's no precise way
to translate belly measurements into waist circumference. But most
people have a sense of whether they have a big belly, she said. And if
they do, the new study suggests they should get rid of it, she said.
It's not clear why abdominal fat would promote dementia, but it may pump out substances that harm the brain, she said.
Dr.
Jose Luchsinger of the Columbia University Medical Center in New York,
who studies the connection between obesity and Alzheimer's disease but
didn't participate in the new work, cautioned that such a study cannot
prove abdominal fat promotes dementia.
But the study results are
"highly plausible" and "I'm not surprised at all," he said. High
insulin levels might help explain them, he said.
Dr. Samuel
Gandy, who chairs the medical and scientific advisory council of the
Alzheimer's Association, said the results fit in with previous work
that indicates a person's characteristics in middle age can affect the
risk of dementia in later life.
And it's another example of how
traits associated with the risk of developing heart disease are also
linked to later dementia, he said.