RSNA Press Release

• Researchers found that an active lifestyle can preserve brain structure in older adults.
• Lifestyle factors examined included recreational sports, gardening and yard work, bicycling, dancing and riding an exercise cycle.
• More than 35 million people worldwide have dementia.

CHICAGO—An active lifestyle helps preserve gray matter in the brains of older adults and could reduce the burden of dementia and Alzheimer's disease (AD), according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA).

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Cyrus Raji, M.D., Ph.D.

Dementia exacts a staggering toll on society. More than 35 million people worldwide are living with the disease, according to the World Health Organization, and the prevalence is expected to double by 2030. AD is the most common cause of dementia and currently has no cure.

Cyrus Raji, M.D., Ph.D., radiology resident at the University of California in Los Angeles, and colleagues recently examined how an active lifestyle can influence brain structure in 876 adults, average age 78 years, drawn from the multisite Cardiovascular Health Study. The patients' condition ranged from normal cognition to Alzheimer's dementia.

"We had 20 years of clinical data on this group, including body mass index and lifestyle habits," Dr. Raji said. "We drew our patients from four sites across the country, and we were able to assess energy output in the form of kilocalories per week."

The lifestyle factors examined included recreational sports, gardening and yard work, bicycling, dancing and riding an exercise cycle.

The researchers used magnetic resonance imaging (MRI) and a technique called voxel-based morphometry to model the relationships between energy output and gray matter volume.

"Voxel-based morphometry is an advanced method that allows a computer to analyze an MR image and build a mathematical model that helps us to understand the relationship between active lifestyle and gray matter volume," Dr. Raji said. "Gray matter volume is a key marker of brain health. Larger gray matter volume means a healthier brain. Shrinking volume is seen in Alzheimer's disease."

After controlling for age, head size, cognitive impairment, gender, body mass index, education, study site location and white matter disease, the researchers found a strong association between energy output and gray matter volumes in areas of the brain crucial for cognitive function. Greater caloric expenditure was related to larger gray matter volumes in the frontal, temporal and parietal lobes, including the hippocampus, posterior cingulate and basal ganglia. There was a strong association between high energy output and greater gray matter volume in patients with mild cognitive impairment and AD.

"Gray matter includes neurons that function in cognition and higher order cognitive processes," Dr. Raji said. "The areas of the brain that benefited from an active lifestyle are the ones that consume the most energy and are very sensitive to damage."

A key aspect of the study was its focus on having variety in lifestyle choices, Dr. Raji noted.

"What struck me most about the study results is that it is not one but a combination of lifestyle choices and activities that benefit the brain," he said.

Dr. Raji said the positive influence of an active lifestyle on the brain was likely due to improved vascular health.

"Virtually all of the physical activities examined in this study are some variation of aerobic physical activity, which we know from other work can improve cerebral blood flow and strengthen neuronal connections," he said.

"Additional work needs to be done," Dr. Raji added. "However, our initial results show that brain aging can be alleviated through an active lifestyle."

Coauthors are H. Michael Gach, Ph.D., Owen Carmichael, Ph.D., James T. Becker, Ph.D., Oscar Lopez, M.D., Paul Thompson, Ph.D., William Longstreth, M.D., Lewis Kuller, M.D., and Kirk Ericson, Ph.D.

Note: Copies of RSNA 2012 news releases and electronic images will be available online at RSNA.org/press12 beginning Monday, Nov. 26.

RSNA is an association of more than 50,000 radiologists, radiation oncologists, medical physicists and related scientists promoting excellence in patient care and health care delivery through education, research and technologic innovation. The Society is based in Oak Brook, Ill. (RSNA.org)

Editor's note: The data in these releases may differ from those in the published abstract and those actually presented at the meeting, as researchers continue to update their data right up until the meeting. To ensure you are using the most up-to-date information, please call the RSNA Newsroom at 1-312-949-3233.

For patient-friendly information on MRI, visit RadiologyInfo.org.

Press conference video

Video clips

• (.mp4 format)
1. Video clip (3,992 Kbyte)
   This video shows a three-dimensional representation of the human brain with results from the multi-site Cardiovascular Health Study of 876 patients shown. The first set of images shows the right and left hemispheres of the brain with green, yellow, and red colors showing how with more calories burned in a variety of lifestyle activities, the larger gray matter volume becomes. Larger gray matter volume with aging means a healthier brain.
   
   The second set of images shows the same results in persons with Alzheimer's dementia. In both series of images, an increased amount of calories burned is related to larger gray matter volumes in brain areas important for memory function such as the temporal and frontal lobes. The final series of images summarizes the results of the entire study showing that a variety of lifestyle activities from dancing to hiking to gardening improves brain health in aging and Alzheimer's disease.
2. Video clip (6,399 Kbyte)
   This video bridges the results of prior work done by Dr. Raji and his collaborators on obesity and brain shrinkage with the results of the current study showing how an active lifestyle improves brain structure in both normal individuals and persons with Alzheimer's. While certain lifestyle factors such as obesity are related to shrinkage as shown in the video and increase risk for Alzheimer's disease, other factors including a diversity of physical activities such as dancing, cycling and gardening can build a better brain. This is thought to occur by improving blood flow and delivery of oxygen and glucose to neurons leading to larger gray matter volumes and improved brain health with aging. The final portion of the video cites published work by Dr. Raji and his collaborators, in addition to the work presented at RSNA 2012, which supports this model of how powerfully positive or negative lifestyle influences the brain.

Images (.JPG format)

Figure 1. This is an image of the cerebral hemispheres in profile showing the main effect of burning calories from a combination of different lifestyle activities on brain structure in 876 elderly individuals. A higher level of calories burned from this variety of lifestyle factors is related to larger gray matter volumes in areas of the brain important for cognitive function including the anterior cingulate gyrus and temporal lobes. The magnitude of the effect is represented by the varying green, yellow, and red colors. Hotter colors, such as red, indicate a stronger effect. High-res (TIF) version (Right-click and Save As)

Figure 2. This figure is of the cerebral hemispheres in profile showing the interaction effect of burning calories from a variety of lifestyle activities on brain structure in persons with Alzheimer's dementia. Gray matter structure in this group is larger in persons who burn a larger number of calories with different lifestyle activities. The brain areas protected by these lifestyle activities are the posterior cingulate and temporal lobes, regions that are targeted by the pathology of Alzheimer's disease. High-res (TIF) version (Right-click and Save As)

Figure 3. This figure summarizes the results of the prior two figures onto one slide to show that caloric burn from a diversity of lifestyle activities benefits gray matter and the brain in aging and Alzheimer's disease. High-res (TIF) version (Right-click and Save As)