Extra Pounds at Midlife May Boost Dementia Risk Later

By Kathleen Doheny, HealthDay

Being merely overweight in middle age raised risk by 70 percent compared to normal-weight peers, experts find.

 

TUESDAY, May 3 2011  (HealthDay News) — Being overweight during middle age may increase your risk of developing dementia later on, a new Swedish study suggests. 

Several studies have already linked obesity in middle age to dementia in later life, but it was unclear whether merely carrying some extra pounds in midlife was a risk factor. The new research suggests that even being overweight — defined as having a body mass index (BMI) of 25 to 30 — is linked with a higher risk of dementia. 

"Being overweight at midlife increased the risk of dementia in late life by more than 70 percent," said lead study author Dr. Weili Xu, a postdoctoral researcher at Karolinska Institute in Stockholm.

Being obese raised the risk even more, to nearly fourfold.

"Although the effect of midlife overweight on dementia is not as substantial as that of obesity, its impact on public health is significant," Xu said, noting that 1.6 billion adults worldwide are obese or overweight, including 50 percent of adults in the United States and Europe.

The study is published in the May 3 issue of Neurology.

In her study, Xu analyzed information from the Swedish Twin Registry. It included data on 8,534 twins aged 65 and older. Of those, 350 were diagnosed with dementia and 114 with possible dementia.

Thirty years earlier, the participants had provided what then must have seemed like mundane data: their height and weight.

That data would prove invaluable as Xu grouped them according to their BMIs, from underweight to obese (having a BMI higher than 30). Nearly 30 percent, she found, were either overweight or obese during midlife.

Further analysis showed that being overweight or obese in midlife independently increased the risk of later dementia, including Alzheimer's and vascular dementia.

About 26 percent of participants without dementia had been overweight at midlife, compared to 36 percent of those with possible dementia and 39 percent with diagnosed dementia.

And although 2.7 percent of seniors without dementia had been obese at midlife, 6.9 percent of those with dementia had been obese, as well as 5.3 percent of those with possible dementia.

When Xu analyzed twin pairs in which one had dementia in later life and one did not, she found the link to weight no longer significant, suggesting early environment and genetics also play roles in dementia.

Why the weight-dementia link? Several mechanisms could explain it, Xu said. A higher BMI is linked with diabetes and vascular disease, which is in turn related to the risk of dementia. Higher weight at midlife may reflect a long period of exposure to higher inflammation throughout the body, which has been linked with lower cognitive function.

Xu and her colleagues noted several study limitations, including the notion that BMI may not be the perfect measure of body fat composition.

They also noted that in terms of lowering dementia risk, it's never too late to start reducing body fat.

The study has a number of strengths, including the large number of people studied, according to Dr. Gary Kennedy, director of geriatric psychiatry at Montefiore Medical Center and professor of psychiatry and behavioral science at Albert Einstein College of Medicine in the Bronx.

Although the study finds a link between being overweight in midlife and dementia risk, it does not prove cause-and-effect, he said. Still, there is evidence that fatty tissue secretes inflammatory cytokines and other chemicals. These may have a direct effect on the brain, he said, inflicting damage to the neurons.

Dr. Gisele Wolf-Klein, director of geriatric education at the North Shore-Long Island Jewish Health System in Hyde Park, N.Y., said the study "is of great relevance in view of the growing epidemic of obesity in both the United States and Europe."

Alzheimer's: A Woman's Disease?

By Dennis Thompson Jr. | Medically reviewed by Pat F. Bass III, MD, MS, MPH

Women are more likely to develop Alzheimer's disease and other forms of dementia than men — but why?

There are many theories as to what may cause Alzheimer's disease but here’s one thing researchers know for sure: Women are diagnosed with various forms of dementia, including Alzheimer's, at greater rates than men. In fact, the Alzheimer’s Association’s 2011 Alzheimer’s Disease Facts and Figures report shows that 3.4 million of the 5.4 million Americans living with Alzheimer’s are female.

Why the Gender Discrepancy?

The current state of research seems to favor the simplest explanation for this phenomenon: Women just live longer. According to Malaz Boustani, MD, assistant professor of medicine at the Indiana University School of Medicine and a center scientist with the Indiana University Center for Aging Research, "Alzheimer's disease depends so much on time. Men tend to die earlier, and therefore they have less prevalence of Alzheimer's. There is a mortality difference."

On average, a girl born in 2005 is expected to live to age 80, according to the U.S. Centers for Disease Control and Prevention. A boy born that same year is expected to live to age 75. According to current consensus, that's why more women tend to develop Alzheimer's disease. They are simply more vulnerable to the greatest risk factor associated with Alzheimer's: advancing age.

Alzheimer's Symptoms in Men Vs. Women

Alzheimer's also appears to affect men and women differently. Here are some ways in which the condition can present itself in men versus women:

• Men with Alzheimer's disease tend to develop more aggression — physical, verbal, and sexual — than women do as the disease progresses. They also tend to wander and perform socially inappropriate actions more frequently than women diagnosed with Alzheimer's.
• Women with Alzheimer's disease tend to become more reclusive and emotionally unstable. They hoard items more often than men do, refuse help more often, and exhibit laughter or crying at inappropriate moments. They also seem more vulnerable to depression and to suffering from delusions.

Alzheimer's Risk: Other Roles Gender Might Play

New studies have found that hormonal differences might also play a role in increasing the risk of Alzheimer's in women. Beyond that, there appear to be gender differences in which risk factors for Alzheimer's affect men and women. Gender also appears to affect how Alzheimer's develops, since men and women exhibit different symptoms of dementia.

Gender is a factor in Alzheimer's disease for "a combination of reasons," says Allen Levey, MD, chair of neurology at Emory University School of Medicine and director of the Emory Center for Neurodegenerative Disease and Alzheimer’s Disease Center. "There are more women who are living longer. There may also be an increased risk for women beyond that. There has been a lot of research pointing toward the effects of female hormones, like estrogen, on dementia."

One study, for instance, has found that hormone replacement therapy can increase a person's risk of developing dementia. Another study found that high or low levels of a thyroid hormone called thyrotropin may be associated with an increased risk of Alzheimer's disease in women.

Gender also seems to play a role in which risk factors matter in the development of dementia. A French study found that men who had suffered a stroke were three times more likely to develop dementia, while stroke seemed to have no effect at all as a risk factor in women. But women with depression were twice as likely to suffer from dementia, and women unable to live without assistance due to an inability to perform routine tasks were 3.5 times more likely to develop dementia.

Researchers will continue to probe these gender differences in hopes of finding different ways to help men and women with Alzheimer's disease and, perhaps, find new treatments or, eventually, a cure.

 

What's the Difference Between Alzheimer's and Dementia

When someone is told they have dementia, it means they have significant memory problems as well as other cognitive difficulties. Most of the time dementia is caused by Alzheimer's disease.

In many parts of the world the words Alzheimer's and dementia are used interchangeably.

While dementia is an all encompassing term, Alzheimer's disease relates to a specific type of dementia.

Contrary to what some people may think, dementia is not a less severe problem, with Alzheimer's disease being a more severe problem.

There is great confusion about the difference between Alzheimer's and dementia.

In a nutshell, dementia is a syndrome, and Alzheimer's is the cause of the symptom.

When someone is told they have dementia, it means that they have significant memory problems as well as other cognitive difficulties, and that these problems are severe enough to get in the way of daily living.

Too often, patients and their family members are told by their doctors that the patient has been diagnosed with “a little bit of dementia.” They leave the doctor’s visit with a feeling of relief that at least they don’t have Alzheimer’s disease (AD).

The confusion is felt on the part of patients, family members, the media, and even health care providers. This article provides information to reduce the confusion by defining and describing these two common and often poorly understood terms.

What's the difference between Alzheimer's disease and dementia?

• “Dementia” is a term that has replaced a more out-of-date word, “senility,” to refer to cognitive changes with advanced age.
• Dementia includes a group of symptoms, the most prominent of which is memory difficulty with additional problems in at least one other area of cognitive functioning, including language, attention, problem solving, spatial skills, judgment, planning, or organization.
• These cognitive problems are a noticeable change compared to the person’s cognitive functioning earlier in life and are severe enough to get in the way of normal daily living, such as social and occupational activities.

A good analogy to the term dementia is “fever.” Fever refers to an elevated temperature, indicating that a person is sick. But it does not give any information about what is causing the sickness.

In the same way, dementia means that there is something wrong with a person’s brain, but it does not provide any information about what is causing the memory or cognitive difficulties.

Dementia is not a disease; it is the clinical presentation or symptoms of a disease. There are many possible causes of dementia. Some causes are reversible, such as certain thyroid conditions or vitamin deficiencies. If these underlying problems are identified and treated, then the dementia reverses and the person can return to normal functioning.

However, most causes of dementia are not reversible. Rather, they are degenerative diseases of the brain that get worse over time. The most common cause of dementia is AD, accounting for as many as 70-80% of all cases of dementia.

Approximately 5.3 million Americans currently live with Alzheimer's Disease.

• As people get older, the prevalence of Alzheimer's disease increases, with approximately 50% of people age 85 and older having the disease. 
• It is important to note, however, that although Alzheimer's is extremely common in later years of life, it is not part of normal aging. For that matter, dementia is not part of normal aging.
• If someone has dementia (due to whatever underlying cause), it represents an important problem in need of appropriate diagnosis and treatment by a well-trained health care provider who specializes in degenerative diseases.

In a nutshell, dementia is a symptom, and Alzheimer's Disease is the cause of the symptom. 

When someone is told they have dementia, it means that they have significant memory problems as well as other cognitive difficulties, and that these problems are severe enough to get in the way of daily living.

Most of the time, dementia is caused by the specific brain disease, AD. However, some uncommon degenerative causes of dementia include vascular dementia (also referred to as multi-infarct dementia), frontotemporal dementia, Lewy Body disease, and chronic traumatic encephalopathy.

Contrary to what some people may think, dementia is not a less severe problem, with AD being a more severe problem.

Test Your Memory for Alzheimer's and Dementia

• There is not a continuum with dementia on one side and AD at the extreme. Rather, there can be early or mild stages of AD, which then progress to moderate and severe stages of the disease.
• One reason for the confusion about dementia and AD is that it is not possible to diagnose AD with 100% accuracy while someone is alive. Rather, AD can only truly be diagnosed after death, upon autopsy when the brain tissue is carefully examined by a specialized doctor referred to as a neuropathologist.
• During life, a patient can be diagnosed with “probable AD.” This term is used by doctors and researchers to indicate that, based on the person’s symptoms, the course of the symptoms, and the results of various tests, it is very likely that the person will show pathological features of AD when the brain tissue is examined following death.

In specialty memory clinics and research programs, such as the BU ADC, the accuracy of a probable AD diagnosis can be excellent. And with the results of exciting new research, such as that being conducted at the BU ADC, the accuracy of AD diagnosis during life is getting better and better. This contribution was made by Dr. Robert Stern, Director of the BU ADC Clinical Core.