Cyrus Raji MD, PhD, Presenter: Nothing to Disclose

Kirk Ericson PhD, Abstract Co-Author: Nothing to Disclose

Oscar Lopez MD, Abstract Co-Author: Nothing to Disclose

James T. Becker PhD, Abstract Co-Author: Nothing to Disclose

Owen Carmichael PhD, Abstract Co-Author: Nothing to Disclose

H. Michael Gach PhD, Abstract Co-Author: Nothing to Disclose

Paul Thompson PhD, Abstract Co-Author: Nothing to Disclose

William T. Longstreth MD, Abstract Co-Author: Nothing to Disclose

Lewis H. Kuller MD, Abstract Co-Author: Nothing to Disclose

Prior work suggests that engagement in physical activity can mitigate brain atrophy in the elderly, but the precise nature of this relationship across the ranges of caloric expenditure and cognitive function is unclear. The main purpose of this study was to assess, in elderly participants spanning a range from normal cognition to Alzheimer’s dementia, energy output from caloric expenditure as a predictor of MRI-based gray matter (GM) volume.

All subjects in this study were recruited from the Institutional-Review-Board-approved Cardiovascular Health Study (CHS), a four-site population-based longitudinal study of coronary heart disease and stroke in persons aged 65 years and older. The present study utilized a sub-sample of 876 participants (mean age 78.3) who had: i) Energy output assessed as kilocalories per week using the standardized Minnesota Leisure-Time Activities questionnaire and binned into quartiles; ii) Cognitive assessments for clinical classification of normal cognition, mild cognitive impairment (MCI), and Alzheimer's dementia (AD); and iii) T1-weighted volumetric MR imaging of the brain. We used voxel-based morphometry (VBM) to model the relationships between energy output and local GM volume while controlling for head size, age, sex, white matter lesion burden, body mass index, clinical classification, and clinic site. We then used membership in the top quartile of energy output to assess moderating influences of high energy output in MCI or AD. Multiple comparisons were accounted for using a 5% False Discovery Rate.

Figure 1a shows in color locations where greater caloric expenditure was associated with greater GM volumes in frontal, temporal, and parietal lobes (False Discovery Rate p-value < .05). Implicated regions include the hippocampus, thalamus, and basal ganglia. Figure 1b shows the positive benefits of higher energy output on the posterior hippocampus (r = .15, adjusted for covariates), in crosshairs. High-energy output was associated with greater GM volume in persons with MCI and AD in the precuneus, posterior cingulate, and cerebellar vermis.

Higher energy output is associated with greater preservation of brain structure across a range from normal cognition to clinical dementia.

MR imaging provides regionally specific quantitative data on the neuroprotective and disease moderating influence of physical activity on the brain.

Raji, C, Ericson, K, Lopez, O, Becker, J, Carmichael, O, Gach, H, Thompson, P, Longstreth, W, Kuller, L, Energy Expenditure Is Associated with Gray Matter Structure in Normal Cognition, Mild Cognitive Impairment, and Alzheimer’s Dementia.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12022971.html