’A fat belly increases the risk of dementia regardless of overall body weight, researchers say. But they found the risk factor jumped by a whopping 260 per cent for obese people.
Anyone with spare tire more vulnerable to diseases such as Alzheimer’s, researchers say
By SHERYL UBELACKER The Canadian Press
Thu. Mar 27 - 4:48 AM
"TORONTO — Carrying a spare tire on the abdomen is known to significantly boost the risk for diabetes and cardiovascular disease, but new research suggests excess belly fat in middle-age also may contribute to Alzheimer’s and other forms of dementia later in life.
In fact, a long-term study of more than 6,000 people found that those with the highest amount of abdominal fat in their 40s were significantly more likely to develop dementia than those with the lowest amount of fat around their mid-sections.
Having a bulging belly increased the risk of dementia regardless of whether participants had normal weight overall or were overweight or obese, as measured by body mass index (BMI), said principal investigator Rachel Whit-mer, a research scientist at Kaiser Permanente, a non-profit U.S. health plan that conducted the study.
Furthermore, the increased risk of Alzheimer’s and other dementias existed independently of other health conditions, including diabetes, stroke and heart disease — and the effect did not vary by race or gender, Whitmer said from Oakland, Calif.
The study, published today in the journal Neurology, found that those who were overweight by BMI standards and also had a big belly were 2.3 times more likely to develop dementia than people with a normal weight and abdominal profile, she said.
Those who were both obese and big around the middle were 3.6 times — or a whopping 260 per cent — more likely to develop dementia than those of normal weight and belly size.
That compares to an 80 per cent higher risk for people who were overweight or obese but did not have a distended abdomen.
"So there’s two messages here," Whitmer said. "The first message is that if you are normal and you have a large belly, your risk for dementia was about the same as those who were overweight or obese who didn’t have a large belly."
"Now, if you are overweight or obese and you have a large belly, your risk really goes up."
"So this really nicely shows that the effect of the large belly was above and beyond the effect of body mass index and, in particular, the magnitude of the effect of the large belly got greater as you weighed more."
The study involved 6,583 people in northern California, aged 40 to 45, who had their abdominal fat measured between 1964 and 1973 and whose health records were followed over time.
An average of 36 years later, when participants were in their 70s, 16 per cent had been diagnosed with dementia.
Whitmer said the kind of fat that settles in the belly, known as visceral fat, has a different makeup and effects on the body than fat elsewhere in the body, which is called subcutaneous fat.
"And fat biologists know, that visceral fat, it is more lively, it is more toxic, it is more metabolically active," said Whitmer. "It secretes a lot of hormones and inflammatory compounds."
While only speculating, she suggests one or more of these inflammatory substances may be able to cross into the brain and cause damage — just as they may do to blood vessels and organs like the heart and pancreas.
"It’s not a causal study, it’s not a mechanistic study," she said.
"But I think our findings suggest there is a pathway going on that is something intrinsic to that belly size, to that belly fat, because we did take into account other diseases that are highly correlated with belly size and highly correlated with dementia."
Dr. Jean-Pierre Despres, a specialist in obesity and cardiovascular disease at Laval University, said he is not surprised to see a relationship between excess abdominal fat and dementia.
"Obviously this is an association and you don’t want to speculate too much on the mechanism behind such associations," Despres said Wednesday from Quebec City.
"But if you think about the consequences of abdominal obesity, of having fat at the wrong place, we know that having too much abdominal fat is associated with what I call a minestrone soup of abnormalities, increasing the risk of Type 2 diabetes, but also increasing the risk of cardiovascular disease."
"Now I’m learning today that on top of the risk of heart disease, the risk of diabetes, this is one more complication to add to the expanding list, which makes this extremely interesting," said Despres, who was not involved in the study.
Whitmer said the findings suggest people need to keep an eye not only on the scale but also on their waist size and where they carry any extra pounds.
But the findings don’t represent all bad news, she stressed.
"On the one hand, yes it’s a bummer that large belly is related to dementia, but this is a modifiable risk factor . . . it is actually less stubborn than the subcutaneous fat, so you can get rid of that fat with exercise and with diet."