Caroline Cassels

July 30, 2012

July 30, 2012 (Vancouver, British Columbia) — Mild cognitive impairment (MCI) with memory loss, also known as amnestic MCI (aMCI), is linked to an increased risk for death. Furthermore, MCI with or without memory loss is linked to an increased risk for social isolation, new research shows.

Presented here at the Alzheimer's Association International Conference (AAIC) 2012, 2 new studies indicate that older adults with aMCI were significantly more likely to die and to be socially isolated compared with those without the condition.

According to investigators, mortality rates in patients with MCI are largely unknown and may be influenced by APOE-4 status.

The first study, conducted by investigators at the Albert Einstein College of Medicine of Yeshiva University in New York City, showed that older adults with aMCI had more than double the risk for death compared with their cognitively normal counterparts. Furthermore, those with dementia were more than 3 times more likely to die.

"I was actually surprised that amnestic MCI was such a strong risk factor for death. In a world where we think of amnestic mild cognitive impairment as an early stage of Alzheimer's disease and we think of death as something that comes really late in the course of the illness, I was surprised that the findings were so strong and robust," principal investigator Richard Lipton, MD, told Medscape Medical News.

First Study of Its Kind

Dr. Lipton added that to his knowledge, this is the first study to look at aMCI and mortality risk.

Although it is known that older individuals with dementia have higher mortality rates than those without dementia, little is known about mortality rates in those with MCI, said Dr. Lipton.

The study included 773 individuals enrolled in the Einstein Aging Study and systematically recruited from Medicare and registered voters lists. All participants were aged 70 years or older and had at least 1 follow-up annual visit. Information about APOE-4 status was available for all participants.

The study cohort was 60.4% female, and 26.6% were black. The mean education level was 13.5 years, and the mean age at enrollment was 78.8 years.

At baseline, 24 (3.3%) had dementia, 76 (10.3%) had aMCI, and 65 (8.9%) had nonamnestic MCI (naMCI).

Participants were followed for an average of 5 years and for up to 16 years. Deaths were reported by a family member or friend designated by the participant. The information was supported by databases, including the National Death and Social Security Death indices.

A Real Disorder

Investigators found that after adjusting for APOE-4 status and comorbidities, aMCI was a risk factor for all-cause mortality (hazard ratio [HR], 2.17; 95% confidence interval [CI], 1.50 - 3.15), whereas naMCI was not.

The adjusted hazard ratio for dementia was 3.26 (95% CI, 1.85 - 5.75).

"There are those who believe that aMCI is sort of a made up condition. At least part of the reason for this is that memory complaints are a ubiquitous part of the aging process. Virtually every older adult will tell you that their memory isn't as good as it was 10 years ago.

"But this study supports the idea that it is a real disorder that is linked to a number of serious outcomes — among them, Alzheimer's dementia and death itself," said Dr. Lipton

He added that these results should increase clinicians' motivation to identify aMCI and intervene early with the ultimate goal of preventing dementia.

Other strategies, he said, include encouraging patients to participate in cognitive activities such as solving crosswords, playing chess or bridge, and reading, which have been shown to preserve youthful cognitive function and delay dementia onset. Similarly, social engagement may also stave off dementia.

In addition, he said, eating a diet that includes fruits and vegetables, olive oil, and fish as primary calorie sources as well as regular physical activity can also preserve cognition.

Social Isolation

In a second study, researchers at the Oregon Health and Science University in Portland found that patients with MCI became increasingly socially isolated as their disease progressed.

According to investigators, the development of MCI may be associated with decreased levels of social engagement. However, they note, quantifying social withdrawal is challenging because it often relies on self-report.

The researchers hypothesized that unobtrusive home-based sensing technologies would better detect subtle changes in activity indicative of MCI.

The study included 148 participants, including 28 with MCI, enrolled in the Intelligent Systems for Assessing Aging Change (ISAAC) trial. The mean age of study participants was 84.2 years; they were followed for a period of up to 3 years.

During that time, their homes were fitted with motion sensors and contact sensors on key doors to assess whether people with MCI spent less time out of their homes as the condition progressed.

In the first month of the study, participants spent an average of 4.5 hours per day outside the home; no difference was observed between those with MCI and their cognitively normal counterparts.

Staying Engaged

During the last month of the trial, those without MCI spent an average of 4.5 hours a day outside the home compared with 2.4 hours a day for those with MCI.

"These findings suggest a progressive narrowing of interaction with the outside world. This very likely diminishes quality of life and could potentially impact the progression of the disease," principal investigator Jeffrey Kaye, MD, said in a statement.

"In addition, this study method may be an innovative way to unobtrusively measure the progression of cognitive impairment and report in real time how effective treatments are in maintaining socialization and engagement with the community," Dr. Kaye added.

Commenting on both studies, Ronald Petersen, PhD, MD, who is a member of the Alzheimer's Association Board of Directors, said the studies highlight the challenges of MCI patients and their families and emphasize "the need for physician education to better manage their cognitive impairment and its broader impact on a person's physical, mental, and social health."

Dr. Lipton, Dr. Kaye, and Dr. Petersen, have disclosed no relevant financial relationships.

Alzheimer's Association International Conference (AAIC) 2012. Abstracts P2-166 and P3-089. Presented July 16 and July 17, 2012.


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