Table 3 Brain Imaging Studies of Patients With Increased Adiposity, Without Symptomatic Cardiovascular, Cerebrovascular, and Peripheral Vascular
Disease
Subject Age,
First Author
No. of
Treatment of
yrs,
(Ref. #)
Study Design
Subjects
Imaging Modality
Imaging Findings
Obesity
Mean (SD)
34 (7)
1. Negative correlations between BMI and
N = 21
Volkow et al.
(63)
3 with BMI
Fluorodeoxyglucose
rCMRglu in left and right prefrontal
No treatment data
positron emission
regions and anterior cingulate gyrus.
reported.
tomography: resting
2. Neuropsychological performance was
state
negatively correlated with prefrontal
Cross-sectional
≥30 (obese)
metabolism (bilateral) and with BMI.
1. Subjects with a BMI >25 demonstrated
Willeumier et 18 with BMI
41 (18)
al. (62)
Cross-sectional
No treatment data
global decreases in rCBF compared with
reported.
subjects with a BMI <25.
>25 (obese)
18 with BMI
SPECT (99Tc-HMPAO):
2. In subjects with a BMI >25, the largest
cognitive activation
decreases in rCBF were in the left frontal
during continuous
superior orbital and right frontal
performance task
midorbital cortex, cerebellum, and right
<25 (lean)
precentral and right postcentral cortex.
3. A negative correlation between BMI
and rCBF in the prefrontal cortex.
1
1. A higher BMI, greater waist
circumference, higher waist-to-hip ratio,
Debette et al.
N = 733
N = 67 (9)
Cross-sectional
No treatment data
greater subcutaneous adipose tissue, and
reported.
(50)
greater visceral adipose tissue were all
1. Structural MRI
associated with smaller total cerebral
2. Radiography (CT)-
brain volume.
based measurements of
2. Waist-to-hip ratio, but not BMI, waist
adipose tissue:
circumference, subcutaneous adipose
subcutaneous adipose
tissue, or visceral adipose tissue, was
tissue and visceral
associated with increasing temporal horn
adipose tissue
ventricular volume.
3. None of the anthropometric or
radiographic indexes of adiposity were
associated with white matter
hyperintensity volume.
Marks et al.
(58)
N = 15
66.2 (5.8)
Cross-sectional
7 active subjects:
1. Greater aerobic fitness (VO2 peak) was
engaged in aerobic
moderately associated with greater FA in
activities >180
DTI MRI
the left anterior and middle cingulum
min/week for the
VO2 peak during peak
segments.
previous 10 yrs
exercise (VO2 peak =
2. A higher BMI and greater abdominal
8 sedentary
aerobic fitness)
girth were associated with lower FA in the
subjects: engaged
right posterior cingulum. Abdominal girth
in any physical
uniquely explained 53.9% of the total
2
activity <90
variance in FA in the age-sex-girth
min/week for the
regression model, whereas BMI uniquely
previous 10 yrs
explained 43.9% of the total variance
found in FA in the age-sex-BMI
regression model.
Xu et al. (61)
N = 51
With BMI ≥25, Cross-sectional
29 with BMI
32.1 (9.8)
≥25
With BMI <25,
22 with BMI
26.2 (9.1)
<25
1. FA of the left and right body of the
corpus callosum negatively correlated
No treatment data
with BMI.
DTI MRI
reported.
2. Mean diffusivity of the fornix and right
and left splenium of the corpus callosum
positively correlated with BMI.
N = 95
Walther et al.
(53)
1. A higher BMI was associated with
53 with BMI
No treatment data
Cross-sectional
<25 (lean)
With BMI <25,
22 with
71.0 (9.8)
widespread smaller gray matter volumes
Structural MRI
reported
in both anterior and posterior cortical
regions.
3
25<BMI<30
With
2. When covarying for the effects of
(overweight)
30<BMI≥25,
hypertension, fewer significant areas of
20 with BMI
69.9 (8.1)
negative correlation with BMI remained,
≥30 (obese)
With BMI >30,
including the left orbitofrontal gyrus, right
66.9 (9.9)
inferior and precentral frontal cortex, right
posterior cortex extending from the
parahippocampal gyrus to the fusiform
and lingual gyri, and right posterior and
lateral cerebellar gray matter.
3. Increasing BMI was associated with
larger white matter volumes including the
frontal, temporal, parietal, and occipital
lobes.
4. Executive functioning and memory
performance positively correlated with
gray matter volume in those regions
significantly affected by BMI.
N = 209
1. Obese subjects had smaller whole-brain
21 with BMI
volumes than both lean and overweight
Gunstad et al. ≥30 (obese)
(51)
With BMI ≥30,
No treatment data
Cross-sectional
63 with
45.11 (15.29)
25<BMI<30
(overweight)
participants.
Structural MRI
reported.
2. Obese individuals had smaller total
gray matter volume than both lean and
With
overweight participants.
4
117 with
25<BMI<30,
3. Trend toward smaller parietal and
BMI <25
42.19 (16.46)
temporal regional gray matter volumes in
(lean)
obese individuals.
4. Inverse correlations between BMI and
With BMI <25,
whole-brain volume and gray matter
33.00 (14.57)
volume.
5. No differences across BMI groups in
total white matter volume.
N = 103
17 with BMI
1. FA values were lower in obese subjects
With BMI >30,
>30 (obese)
compared with overweight and lean
51.89 (15.21)
Stanek et al.
31 with
(60)
25<BMI<30
No treatment data
With
Cross-sectional
subjects in the fornix, genu, splenium, and
DTI MRI
reported.
body of the corpus callosum.
25<BMI<30,
(overweight)
2. No FA differences between lean and
45.88 (16)
55 with BMI
overweight subjects.
With BMI <25,
<25 (lean)
42.64 (18.16)
24 with BMI
With BMI ≥25,
Pannacciulli
≥25 (obese)
32 (8)
et al. (55)
36 with BMI
With BMI <25,
<25 (lean)
33 (9)
Structural MRI: gray
1. Obese subjects demonstrated lower
No treatment data
matter and white matter
gray matter density in the right
reported.
density was calculated as cerebellum, left post-central gyrus, right
Cross-sectional
the weighted average of
frontal operculum, right and left putamen,
5
the gray matter and
and right and left middle frontal gyri
white matter voxels
compared with lean subjects.
located in the volume
2. Obese subjects demonstrated higher
defined by the
gray matter density in the left calcarine
smoothing kernel.
cortex, left middle occipital gyrus, left
inferior frontal gyrus, and right cuneus of
compared with lean subjects.
3. BMI was negatively associated with
gray matter density of the left postcentral
gyrus in obese but not lean subjects.
4. Obese subjects demonstrated greater
white matter density in the vicinity of the
striatum compared with lean subjects.
N = 50
With BMI >25,
1. A higher BMI was associated with
5 with BMI
44.9 (7.2)
lower NAA concentration in frontal gray
>25 (obese)
With
matter.
15 with
25<BMI<30,
2. A higher BMI was associated with
25<BMI<30
44.0 (7.6)
Gazdzinski et
al. (56)
No treatment data
(overweight)
With BMI <25,
30 with BMI
40.4 (9.3)
<25 (lean)
lower NAA concentrations in the frontal,
1
Cross-sectional
reported.
H-MRS
parietal, and temporal white matter.
3. A higher BMI was associated with
lower Cho concentration in frontal white
matter.
6
1. A higher BMI was correlated with
lower gray matter volumes in the orbital
frontal cortex, hippocampus, and
N = 94
With BMI ≤25,
subcortical areas including the putamen,
77.5 (4)
globus pallidus, and thalamus.
With
2. A higher BMI was correlated with
29 with BMI
≤25 (lean)
Raji et al.
(52)
51 with
No treatment data
30<BMI≥25,
Cross-sectional
30<BMI ≥25
Structural MRI
lower subcortical white matter volumes.
reported.
77.2 (2.6)
3. The correlations between lower white
(overweight)
matter and gray matter volumes and
14 with BMI
higher BMI remained significant after
≥30 (obese)
With BMI>30
controlling for the effects of type 2
= 76.9 (2.8)
diabetes mellitus.
1. There was a strong correlation between
BMI and leptin level.
2. There was a significant negative
Mueller et al.
(59)
No treatment data
N = 49
Age, 26.4 (5)
Cross-sectional
DTI MRI
correlation between FA and BMI in the
reported.
entire corpus callosum in women only.
3. There was a negative correlation
between axial diffusivity and BMI in all
7
regions of the corpus callosum for both
women and men.
1. A higher BMI was associated with
decreased normalized brain volume.
Ward et al.
(49)
No treatment data
N = 114
54.2 (6.6)
Cross-sectional
Structural MRI
Neither age, cholesterol, nor systolic
reported.
blood pressure mediated the effect of BMI
on normalized brain volume.
1. Negative correlations observed between
BMI and regional gray matter volume of
bilateral medial aspects of the temporal
N = 1,428
lobe, bilateral anterior lobes of the
27 with BMI
cerebellum, bilateral fusiform gyrus,
≥30 (obese)
bilateral frontal lobes, bilateral precuneus,
Taki et al.
(54)
273 with
No treatment data
25<BMI<30
45.48 (15.07)
Cross-sectional
and midbrain in men only.
Structural MRI
reported.
2. Positive correlations observed between
(overweight)
BMI and regional gray matter volume of
1,128 with
bilateral inferior frontal gyri, bilateral
BMI <25
posterior lobe of the cerebellum, bilateral
(lean)
frontal and temporal lobes, bilateral
thalami, and bilateral caudate heads in
men only.
8
3. No correlations of any type observed
between BMI and regional gray matter in
women.
Gazdzinski et N = 23
al. (57)
With
1. Higher BMI was associated with lower
25<BMI<30,
NAA/Cr, lower NAA/Cho, lower Glu/Cr,
68.9 (6.7)
and lower Glu/Cho in the anterior
7 with
25<BMI<30
(overweight)
No treatment data
1
With BMI <25, Cross-sectional
16 with BMI
H MRS
cingulate cortex.
reported.
70.7 (6.5)
2. No relationships between BMI and
<25 (lean)
neurochemical levels were observed in the
posterior cingulate cortex.
Cho = choline; Cr = creatine; FA = fractional anisotropy; Glu = glucose; NAA = N-acetylaspartate; VO2 = oxygen consumption; other abbreviations as in Tables 2 and 3.
9