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Rapid Weight Loss in Seniors Signals Higher Dementia Risk (HealthDay)

TUESDAY, May 19 (HealthDay News) -- Losing weight rapidly late in

life seems to signal a greater risk of experiencing some form of dementia,

new research suggests.

For older adults, "basically, we saw that if you are thinner or are

losing weight at a faster rate, then you are at a higher risk of

developing dementia," said study author Tiffany F. Hughes, a postdoctoral

fellow in the department of psychiatry at the University of Pittsburgh

School of Medicine.

"This is in contrast to other studies that have shown higher BMI in

middle age to increase risk of dementia," she acknowledged. "What is

likely going on is that higher BMI in middle age is a true risk factor for

dementia, while being thinner or losing weight more quickly in old age is

a result of dementia that has not been detected yet."

Hughes, who conducted her research while a doctoral student at

University of South Florida, published the findings in the May 19 issue of

Neurology.

To assess the association, the study authors focused on a group of just

over 1,800 Japanese Americans living in Washington state.

At the launch of the study in 1992, the participants were about 72

years old, on average, at which point all were free of dementia.

Over a period of eight years, Hughes and her colleagues tracked changes

in body mass index (BMI), waist circumference and waist-to-hip ratio among

the members of the study group, and then lined up those statistics against

diagnoses of various forms of dementia, including Alzheimer's disease.

The team found that regardless of smoking history, exercise habits and

gender, having a higher BMI late in life actually appeared to be

associated with having a lower risk for developing Alzheimer's.

Looked at in reverse, the study authors observed that those

participants who had a lower BMI at the study's launch actually faced a 79

percent greater risk for developing dementia.

In addition, participants of any weight who went on to lose pounds

during the study period at a relatively fast rate had a three times higher

risk for developing dementia than those who lost weight more slowly.

In fact, participants of any weight who went on to shed some pounds at

a relatively slow pace over the course of the study period actually

experienced a drop in their risk for developing either dementia or

Alzheimer's.

However, the apparent connection between a drop in dementia risk and

slow weight loss was especially pronounced among men and women who were

either overweight or obese to begin with -- generally more so than among

either normal or underweight participants who similarly lost weight.

Specifically, the team observed that slow-paced weight loss among those

with a BMI of 23 or above translated into an 82 percent drop in the

risk for dementia.

The authors cautioned, however, that the findings could be skewed by

the fact that seniors who began the study at a normal body weight

naturally have fewer pounds to lose, and this could affect the pace at

which any weight loss might have unfolded.

In addition, they noted that the study focused solely on Americans of

Japanese ancestry, making it somewhat difficult to generalize the findings

to other racial and ethnic groups. And they described the amount of time

they spent tracking weight fluctuations as "relatively short," leaving

open the possibility that different patterns of risk could be found if the

same group were to be followed for a longer period.

Yet despite these caveats, Hughes and her colleagues concluded that

having a relatively low BMI in late life appears to be a sign of

underlying dementia-related disease -- particularly if a senior had been

overweight or obese earlier in life.

"Being thin or rapid weight loss alone will not likely tell us who is

going to get dementia," Hughes noted. "But along with other tests it may

help doctors identify those who will, so treatment therapies can be

started earlier."

For his part, Dr. Lon S. Schneider, a professor of psychiatry,

neurology and gerontology at the University of Southern California, Los

Angeles, said that when assessing the implications of this particular

study "the devil is in the details."

"That said, it does seem that weight loss is a warning sign of

something bad to happen," he noted. "Weight loss occurring over the age of

75 or 78 is a problem that predicts bad things in general. It's a major

problem in the management of elderly people with illness. And almost

always the explanation for unexplained weight loss at this age is a few

years down the road. So yes, certainly it is the case that this is a

development that could predict future cognitive impairment."

More information

For additional information and resources on dementia, visit FamilyDoctor.org.

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