Journal of Rehabilitation Medicine 51-10 | Page 63

Effect of exercise on neurotrophin levels in patients with FM
Table III. Changes in nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), levels after the interventions in women
with fibromyalgia (FM)
Exercise
n  =  41
Relaxation
n  =  34
Substance, pg/ml Before
Median (IQR) After
Median (IQR) p-value Before
Median (IQR) After
Median (IQR)
NGF
BDNF 0.26 (0.36)
1,553.00 (2,234.05) 0.24 (0.24)
2,006.33 (2,525.95) 0.331
0.464 0.28 (0.32)
1,695.25 (2,862.37) 0.29 (0.38)
0.199
2,429.67 (3,393.8) 0.467
Between groups
p-value p-value
0.678
0.915
IQR: interquartile range.
Regression of nerve growth factor and brain-derived
neurotrophic factor with cytokines/chemokines at
baseline Changes in nerve growth factor and brain-derived
neurotrophic factor levels after interventions in
fibromyalgia
Using OPLS, it was not possible to significantly reg-
ress BDNF or NGF (i.e. Y variables) using cytokine
and chemokine data as X variables, in all participants
together (n = 100) or in each group separately (FM and
HC, respectively). Hence, no significant multivariate
associations existed between the 2 neurotrophins and
cytokines/chemokines. There was no significant difference in NGF or BDNF
at baseline between the exercise and relaxation groups.
No significant changes were found in NGF and BDNF
levels in FM over time, i.e. before vs after interven-
tions, either in the exercise or in the relaxation group
(Table III).
Regression of nerve growth factor and brain-derived
neurotrophic factor with clinical variables at baseline
783
Using OPLS, it was not possible to regress BDNF
or NGF using the clinical data shown in Table I as X
variables, either in all participants together (n = 100) or
in each group separately (FM and HC, respectively).
Hence, no significant multivariate associations existed
between the 2 neurotrophins and clinical data.
Changes in clinical and functional measures after
interventions in fibromyalgia
Marked differences in outcomes in favour of the exer-
cise group were found for ratings of global pain, as well
as for the physical subscale and the reduced activity
subscale of MFI (i.e. absolute effects sizes > 0.70) (Ta-
ble IV). No significant multivariate relationships were
found between the changes in NGF and BDNF and the
changes in the clinical variables shown in Table IV.
Table IV. Changes in clinical and functional measures after programme of progressive resistance exercise or relaxation therapy. Note:
these results have been published elsewhere (31)
Resistance exercise
n  = 38
Variables
VAS global pain (0–100)
PPT (kPa), right
PPT (kPa), left
HADS-depression (0–21)
HADS-anxiety (0–21)
PCS (0–52)
SF36-PSC (0–100)
SF36-MSC (0–100)
FIQ (0–100)
MFI (0–20)
General fatigue
Physical fatigue
Reduced activity
Reduced motivation
Mental fatigue
Relaxation therapy
n  =  34
Before
Mean (SD) After
Mean (SD) p-value Before
Mean (SD) After
Mean (SD) p-value Effect size
Cohen’s d
49.5 (23.0)
164 (71)
170 (77)
7.7 (4.0)
8.9 (4.5)
21.3 (10.2)
31.2 (7.9)
36.8 (11.9)
62.2 (13.9) 37.2 (23.7)
181 (80)
173 (81)
6.7 (4.6)
8.2 (5.0)
17.5 (10.5)
32.3 (11.8)
38.3 (15.9)
56.0 (18.2) 0.004
0.180
0.803
0.060
0.271
0.003
0.544
0.514
0.023 57.2 (16.9)
196 (93)
194 (94)
7.4 (3.6)
8.6 (4.4)
21.0 (12.6)
27.2 (9.2)
35.5 (13.0)
64.1 (15.3) 54.0 (19.9)
181 (97)
178 (84)
7.5 (4.5)
9.0 (4.7)
18.1 (10.8)
29.4 (7.7)
36.5 (13.0)
62.0 (15.8) 0.324
0.123
0.094
0.644
0.097
0.082
0.147
0.646
0.482 –0.77
–0.01
–0.06
–0.18
–0.17
–0.06
0.30
0.12
–0.36
0.072
0.527
0.781
0.604
0.948 –0.45
–0.82
–0.69
–0.32
–0.44
17.8
16.1
14.9
10.5
15.7
(2.3)
(2.9)
(3.5)
(3.6)
(3.4)
16.7
14.4
13.5
10.1
14.0
(2.9)
(3.6)
(3.9)
(3.7)
(3.7)
0.046
0.023
0.052
0.506
0.009
18.6
17.4
16.1
11.0
15.5
(2.0)
(2.5)
(3.3)
(4.1)
(3.8)
17.9
17.1
15.9
11.3
15.5
(2.5)
(3.0)
(3.4)
(4.0)
(3.1)
The significance of the changes within the groups is illustrated as a p-value. Effect sizes between the 2 groups are presented as Cohen’s d using post-interventional
data (the 2 “After” columns). VAS: visual analogue scale; PPT: pressure pain threshold; HADS: Hospital Anxiety and Depression Scales; PCS: Pain Catastrophizing
Scale; SF36-PSC: Short Form Health Survey 36 (SF36) Physical Summary Component; SF36-MSC: Short Form Health Survey 36 (SF36) Mental Summary
Component; FIQ: Fibromyalgia Impact Questionnaire; MFI: Multidimensional Fatigue Inventory. Significant p-values are shown in bold.
J Rehabil Med 51, 2019