March 13th, 2012
08:01 AM ET
Late-life dementia has a lot in common with heart disease – and many of the same causes, according to an article published Tuesday in Nature Reviews Neurology.
Like heart disease, the cognitive impairment that accompanies aging is usually the result of a combination of lifestyle and other factors, the article says. Diabetes, obesity, untreated hypertension, sedentary lifestyle and stress are all linked to both heart disease and dementia.
Other factors linked to dementia: untreated obstructive sleep apnea, clinical depression, bipolar disorder, vitamin B12 deficiency, post traumatic stress disorder, head trauma, brain injury caused by a lack of oxygen, and the ApoE, or Alzheimer’s, gene.
Lead author Dr. Majd Fotuhi says the latest research shows dementia can be delayed, stopped and sometimes even reversed with lifestyle changes.
Fotuhi, an assistant professor of neurology at Johns Hopkins University School of Medicine, says this is empowering news for anyone worried about dementia or confronting mental decline.
“All of a sudden you can be in charge,” says Fotuhi, who is also chairman of the Neurology Institute for Brain Research and Fitness. He estimates only a fifth of late-life dementia is Alzheimer’s.
Fotuhi and his colleagues reviewed factors that alter the size of the hippocampus. The hippocampus, a pair of almost thumb-sized structures on either side of the brain, is critical for the formation of new memories.
A large hippocampus is associated with good memory and cognitive function; a smaller hippocampus is linked to the development of dementia.
“The hippocampus is very sensitive to a number of environmental factors,” Fotuhi says.
Unlike other structures in the brain, the hippocampus can increase in size in adults. Studies show moderate exercise, mental stimulation, meditation, and treatment for cardiovascular disease, clinical depression and obstructive sleep apnea all increase the size of the hippocampus.
Fotuhi and his co-authors argue that researchers looking into the causes and cures for cognitive decline have placed too much focus on the amyloid plaques that accompany Alzheimer’s dementia.
Arthur Kramer, a professor of psychology at the University of Illinois at Urbana-Champaign, has studied exercise, hippocampus size and memory in older adults.
“I think the news is good that there are steps we can take before that wonder drug is discovered to enhance the health of the brain,” Kramer says. He adds that researchers now need to learn what’s going on in the hippocampus when it increases in volume.
Dr. Christopher Callahan, director of the Indiana University Center for Aging Research, says the article points to the growing body of evidence of the brain’s ability to grow and change, even among older adults.
“There are already many reasons for people to watch their diet and control chronic conditions and increase physical activity,” Callahan says. The challenge for doctors, he adds, is finding ways to motivate patients to change their lifestyles.
“Losing your cognitive skills is up there in terms of what people fear – more than their fear of dying. It could be this is a particular lever to get people to take care of themselves,” Callahan says.
Caleb Finch, a professor of gerontology and biological sciences at USC, cautions that no amount of lifestyle changes can address Alzheimer’s.
“If it’s Alzheimer’s, there’s not much that can be done right now,” Finch says. “By the time Alzheimer’s is even in the earliest stages, there’s been a massive loss of neurons in the hippocampus and cortex. There’s nothing known to prevent or reverse that because the cells are gone.”
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