The effects of physical activity, education, and body mass index on the aging brain.

Department of Neurology, Laboratory of Neuro Imaging, UCLA School of Medicine, Los Angeles, California 90095-7332, USA.
Human Brain Mapping (Impact Factor: 6.92). 09/2011; 32(9):1371-82. DOI: 10.1002/hbm.21113
Source: PubMed

ABSTRACT Normal human aging is accompanied by progressive brain tissue loss and cognitive decline; however, several factors are thought to influence brain aging. We applied tensor-based morphometry to high-resolution brain MRI scans to determine whether educational level or physical activity was associated with brain tissue volumes in the elderly, particularly in regions susceptible to age-related atrophy. We mapped the 3D profile of brain volume differences in 226 healthy elderly subjects (130F/96M; 77.9 ± 3.6 SD years) from the Cardiovascular Health Study-Cognition Study. Statistical maps revealed the 3D profile of brain regions whose volumes were associated with educational level and physical activity (based on leisure-time energy expenditure). After controlling for age, sex, and physical activity, higher educational levels were associated with ~2-3% greater tissue volumes, on average, in the temporal lobe gray matter. After controlling for age, sex, and education, greater physical activity was associated with ~2-2.5% greater average tissue volumes in the white matter of the corona radiata extending into the parietal-occipital junction. Body mass index (BMI) was highly correlated with both education and physical activity, so we examined BMI as a contributing factor by including physical activity, education, and BMI in the same model; only BMI effects remained significant. This is one of the largest MRI studies of factors influencing structural brain aging, and BMI may be a key factor explaining the observed relationship between education, physical activity, and brain structure. Independent contributions to brain structure could not be teased apart as all these factors were highly correlated with one another.

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    ABSTRACT: Aerobic fitness (AF) and self-reported physical activity (srPA) do not represent the same construct. However, many exercise and brain aging studies interchangeably use AF and srPA measures, which may be problematic with regards to how these metrics are associated with brain outcomes, such as morphology. If AF and PA measures captured the same phenomena, regional brain volumes associated with these measures should directly overlap. This study employed the general linear model to examine the differential association between objectively-measured AF (treadmill assessment) and srPA (questionnaire) with gray matter density (GMd) in 29 cognitively unimpaired community-dwelling older adults using voxel based morphometry. The results show significant regional variance in terms of GMd when comparing AF and srPA as predictors. Higher AF was associated with greater GMd in the cerebellum only, while srPA displayed positive associations with GMd in occipito-temporal, left perisylvian, and frontal regions after correcting for age. Importantly, only AF level, and not srPA, modified the relationship between age and GMd, such that higher levels of AF were associated with increased GMd in older age, while decreased GMd was seen in those with lower AF as a function of age. These results support existing literature suggesting that both AF and PA exert beneficial effects on GMd, but only AF served as a buffer against age-related GMd loss. Furthermore, these results highlight the need for use of objective PA measurement and comparability of tools across studies, since results vary dependent upon the measures used and whether these are objective or subjective in nature.
    Frontiers in Aging Neuroscience 01/2015; 7. DOI:10.3389/fnagi.2015.00005 · 2.84 Impact Factor
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    ABSTRACT: The objective of this longitudinal magnetic resonance (MR) imaging study was to examine the effects of endurance training on hippocampal and grey matter volumes in schizophrenia patients and healthy controls. 20 chronic schizophrenia patients and 21 age- and gender-matched healthy controls underwent 3months of endurance training (30 min, 3 times perweek). 19 additionally recruited schizophrenia patients played table soccer (“foosball” in the USA) over the same period. MR imaging with 3D-volumetric T1-weighted sequences was performed on a 3 T MR scanner at baseline, after 6 weeks and after the 3-month intervention and 3 additional training-free months. In addition to voxel-based morphometry (VBM), we performed manual and automatic delineation of the hippocampus and its substructures. Endurance capacity and psychopathological symptoms were measured as secondary endpoints. No significant increases in the volumes of the hippocampus or hippocampal substructures were observed in schizophrenia patients or healthy controls. However, VBM analyses displayed an increased volume of the left superior, middle and inferior anterior temporal gyri compared to baseline in schizophrenia patients after the endurance training, whereas patients playing table soccer showed increased volumes in the motor and anterior cingulate cortices. After the additional training-free period, the differenceswere no longer present.While endurance capacity improved in exercising patients and healthy controls, psychopathological symptoms did not significantly change. The subtle changes in the left temporal cortex indicate an impact of exercise on brain volumes in schizophrenia. Subsequent studies in larger cohorts are warranted to address the question of response variability of endurance training.
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    ABSTRACT: Obesity, commonly measured with body mass index (BMI), is associated with numerous deleterious health conditions including alterations in brain integrity related to advanced age. Prior research has suggested that white matter integrity observed using diffusion tensor imaging (DTI) is altered in relation to high BMI, but the integrity of specific white matter tracts remains poorly understood. Additionally, no studies have examined white matter tract integrity in conjunction with neuropsychological evaluation associated with BMI among older adults. The present study examined white matter tract integrity using DTI and cognitive performance associated with BMI in 62 healthy older adults (20 males, 42 females) aged 51-81. Results revealed that elevated BMI was associated with lower fractional anisotropy (FA) in the uncinate fasciculus, though there was no evidence of an age by BMI interaction relating to FA in this tract. No relationships were observed between BMI and other white matter tracts or cognition after controlling for demographic variables. Findings suggest that elevated BMI is associated with lower structural integrity in a brain region connecting frontal and temporal lobes and this alteration precedes cognitive dysfunction. Future studies should examine biological mechanisms that mediate the relationships between BMI and white matter tract integrity, as well as the evolution of these abnormalities utilizing longitudinal designs. Copyright © 2014 Elsevier B.V. All rights reserved.
    Behavioural Brain Research 10/2014; 278C:342-347. DOI:10.1016/j.bbr.2014.10.010 · 3.39 Impact Factor

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