'Pear' Shaped vs. 'Apple' Shaped continued...
Scientists have already shown in previous research that different kinds of fat release different cytokines and have different effects on insulin resistance, lipids, and blood pressure.
"We need to find out if one kind of fat is more detrimental than the other and how it affects brain function," Kerwin says. "The fat may contribute to the formation of plaques associated with Alzheimer's disease or a restricted blood flow to the brain."
The findings should provide guidance to doctors treating or counseling overweight patients, the researchers say.
"The study tells us if we have a woman in our office and we know from her waist-to-hip ratio that she's carrying excess fat on her hips, we might be more aggressive with weight loss," Kerwin says. "We can't change where your fat is located, but having less of it is better."
Alzheimer's Disease: Men vs. Women
The researchers did not address whether their findings in the study on older women may be true for men. Alzheimer's disease, they write, is 1.5 times more likely to develop in women than men.
Previous research also has shown that obesity has been associated with poorer cognitive function in men. They also write that the discrepancy between men and women found in past studies may reflect differences in body weight and distribution of fat.
Kerwin tells WebMD in an email that the most important finding of the study is that "obesity is associated with worse cognitive function and that it has a more pronounced relationship if the woman" is pear-shaped.
"It is true, though, that fat distribution on the body, or the pear-shaped woman, which is a small waist and larger hips, and an apple-shape woman with a larger waist relative to hips and high waist-hip ratio, cannot be controlled and is the same throughout life, even if your weight changes," she says by email.
The study is published in the July 14 issue of the Journal of the American Geriatrics Society.
Kerwin discloses that she has received consultant fees from Pfizer Pharmaceuticals, Forest Laboratories, and Novartis Pharmaceuticals.