CHICAGO — Results of volumetric scans show that widespread adoption of an active lifestyle could reduce cases of Alzheimer’s disease by half. That would mean more than 1 million fewer cases in the U.S. alone, according to researchers at RSNA 2012 Monday.
By using cross-sectional imaging and volumetric scans, researchers were able to create 3D representations of the patients’ brains. They also incorporated a technique known as “voxel-based morphometry” to quantify the amount of gray matter in each patient.
Cyrus Raji, MD, and his colleagues used brain scans of 876 patients averaging 78 years of age. The patients ranged from normal to obese, with an average BMI of 27. A BMI of 25 to 30 is considered overweight. About 25 percent of them had either Alzheimer’s disease or mild cognitive impairment (MCI).
The relationship between two data sets lies at the heart of the study, kilocalories burned per week and gray matter volume. The researchers recorded how many kilocalories (the same kind listed on nutrition labels) each patient burned in a week and compared it to gray matter volume. They then used a computer to create a mathematical model, enabling the researchers to analyze the relationship between the two.
Controlling for factors such as head size, gender and BMI, the researchers found that patients who burned more kilocalories burned had larger volumes in three crucial areas of the brain: temporal lobe, cingulate gyrus and the hippocampus, all of which are important for memory and learning. The brain scans revealed that active patients with Alzheimer’s disease also exhibited greater volumes of gray matter than more sedentary patients with the disease.
“The areas of the brain that are benefitting the most from this active lifestyle are also the areas that are affected in Alzheimer’s disease and are also responsible for cognition,” Raji explained.
Exercise helps the brain in a number of ways, stimulating blood flow and neuron growth and reducing the amyloid plaques, which are symptomatic of Alzheimer’s and damage neurons.
It’s not just one behavior or exercise that produced the positive outcome. Participants’ activities included hiking, swimming, walking, dancing and yard work. Raji said this is the first study that allowed for a variety of physical activities.
“That’s important because it allows individuals to customize whatever physical activity regimen they like,” he said. “Lifestyle is more than one factor. It is a combination of factors that is likely to be the most important.”