Plasma Cytokine Levels in Fibromyalgia and Their Response to 15 Weeks of Progressive Resistance Exercise or Relaxation Therapy

Table 3

PCAs of background data, psychometric, and cytokines in fibromyalgia and healthy controls taken together.

Variables	p[1]	p[2]	p[3]	p[4]
Age	0.06	−0.14	0.34	−0.15
Weight	0.12	−0.06	0.17	0.41
Height	−0.02	−0.19	−0.06	0.19
BMI	0.15	−0.07	0.20	0.36
Systolic BP	0.07	−0.19	0.34	0.13
Diastolic BP	0.08	−0.13	0.34	0.16
VAS global pain intensity	0.29	−0.03	−0.13	0.03
PPT	−0.23	−0.04	0.07	−0.04
Hand grip force	−0.25	−0.03	−0.12	0.33
Elbow flexion force	−0.26	−0.04	−0.13	0.32
Knee extension force	−0.21	−0.02	−0.13	0.40
6MWT	−0.26	0.12	−0.15	0.02
PDI	0.20	−0.07	−0.20	0.02
HADS depression	−0.22	−0.11	0.23	−0.11
HADS anxiety	0.25	−0.07	−0.22	0.10
PCS	0.30	−0.08	−0.13	0.09
SF36-PCS	0.30	−0.07	−0.13	0.06
SF36-MCS	−0.29	0.07	0.05	−0.06
FIQ	−0.24	−0.11	−0.15	0.27
IFN-γ	0.08	0.34	0.11	0.06
IL-1β	0.21	−0.08	−0.23	0.09
IL-2	−0.04	0.20	−0.01	0.03
IL-6	0.06	0.39	0.00	0.13
IL-8	0.00	0.07	0.03	0.11
IL-10	0.09	0.27	0.06	0.07
IL-17A	0.10	0.35	−0.02	0.13
TNF-α	0.07	0.40	0.02	0.10
IL-1ra	0.08	0.36	0.08	0.05
IP-10	0.03	−0.03	0.11	0.06
MCP-1	0.04	0.07	0.21	0.18
eotaxin	0.01	−0.08	0.30	0.08
R^2	0.26	0.11	0.09	0.07
Q^2	0.23	0.08	0.03	0.04

PCA = principle component analysis. Four significant components (p[1]-p [4]) were obtained. For each component are reported the loadings of the included variables. High absolute loadings (>0.20) are most important for the component. Variables with high absolute loadings are intercorrelated; the same sign indicate a positive intercorrelation while different signs for two variables with high loadings indicate a negative correlation. R² and Q² are reported for each component at the two bottom rows. R² (cumulative) = 0.53, Q² (cumulative) = 0.34. The loadings of the most important variables for the four components are denoted with bold type. BMI = body mass index; BP = blood pressure9; FIQ = fibromyalgia impact questionnaire; HADS = hospital anxiety and depression scale; PDI = pain disability index; PPT = pressure pain thresholds (mean of 8 sites); SF36 = Short Form Health Survey 36, physical (PSC) and mental summary components (MSC); 6MWT = 6-min walk test; VAS = visual analogue scale.