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Older adults with cognitive impairment are at a higher risk of death

In a new study about the link between cognitive impairment (thinking and memory problems) and risk of death, published in Sept. 6, 2011 in the Annals of Internal Medicine, the researchers found that older adults who have thinking and memory problems known as cognitive impairment are at a higher risk of death.

"The association between cognitive impairment and death risk was found even for mild impairment," says Greg A. Sachs, MD, professor of medicine and a scientist at the Center for Aging Research, Indiana University School of Medicine.

"When the impairment was moderate to severe, the impact on death risk was as great as for many chronic conditions, like congestive heart failure and diabetes," he tells WebMD.

The link has been studied for about a decade. The new study strengthens the association even more, says Sachs. It's a link, not proven cause and effect.

Tens of millions worldwide have Alzheimer's disease.

Study Details

The researchers studied 3,957 men and women, aged 60 to 102. They were screened at primary care doctors' appointments. The evaluations started between January 1991 and May 1993. They asked 10 questions to assess mental status. Depending on the results, they classified the men and women as having no cognitive impairment, mild, moderate, or severe impairment.

When the impairment is mild, a person has some trouble with attention, language, judgment, memory, reading, and writing. When it progresses and is severe enough to interfere greatly with daily activities, it is termed dementia. Someone with mild impairment, for instance, can't remember appointments or the name of someone newly met.

At the start of the study, 3,157 had no mental impairment, 533 had mild impairment, and 267 had moderate to severe problems. The team followed up to see who had died by Dec. 31, 2006.

By the end of the study, 57% of those with no impairment died. But 68% of those with mild and 79% of those with moderate to severe memory problems died.

The median survival time (half longer, half less) was 138 months for those who had no impairment. It was 106 for those with mild impairment. It was 63 months for those with moderate to severe impairment.

The study, however, had some limitations. Memory and thinking problems were not tracked over time of the study. The men and women were only tested at the start. All patients were from Indianapolis in the United States. They tended to have low education and low socioeconomic status. For that reason, the findings may not apply to everyone.

Some doctors, as well as patients, dismiss problems with memory and thinking as just inevitable with age. The findings are a reminder that cognitive impairment is important for doctors to evaluate. It needs as much attention as doctors typically pay to screening for heart disease and cancers, Sachs says.

Cognitive impairment could be linked to death risk in a number of ways:

- Being at risk for other problems, such as falls.

- Being less likely to follow instructions to take medicine for other chronic conditions.

- Being less likely to follow instructions to eat a healthy diet, increasing their risk of health problems.

To minimize cognitive impairment with age, researchers recommends physical exercise, mental engagement, and social contact.

Experts review

The new study is ''another piece of evidence that mild cognitive impairment is far from a benign condition," says Terry E. Goldberg, PhD, an investigator at the Feinstein Institute for Medical Research.

In his own recent research, Goldberg has found that cognitive information is more accurate at predicting who will progress to Alzheimer's disease than are such changes as brain volume.

To reduce the risk of impairment, he says that physical activity has been shown to have good effects on brain chemicals that affect memory. A healthy diet is also advised.

The findings lend support to the idea that cognitive impairment is not something to be dismissed, says William H. Thies, PhD, chief medical and scientific officer for the Alzheimer's Association. "This paper is really a very solid piece of research work that really is documenting that the more cognitive impairment you have, the sooner you are going to die," he tells WebMD. "We have to start taking dementia seriously and recognize it as a fatal disease."