Table 2.

Results from stepwise regression examining peripheral serum cytokines that predicted clinical motor scores (i.e., tremor scores) in persons with PD, while controlling for age, disease duration, disease duration.

Variables entered	Full Data Set (N ​= ​26)			Exploratory Analysis 1 (N ​= ​23)			Exploratory Analysis 2 (N ​= ​16)
	β	t	p	β	t	p	β	t	p
Step one
Age	.06	.25	.80	−.09	−.31	.75	.077	.22	.83
Disease duration	.45	2.12	.05	.36	1.48	.16	.33	1.08	.31
Hoehn and Yahr	−.22	−.96	.35	−.12	−.45	.65	−.11	−.34	.74
Step two
Age	−.27	−1.36	.19	−.473	−2.07	.05	−.36	−1.43	.19
Disease duration	.46	2.80	.013	.41	2.38	.03	.38	1.86	.10
Hoehn and Yahr IFN-γ	−.26 −.67	−1.47 −3.54	.16 .003	−.13 −.76	−.66 −3.74	.52 .002	−.19 −.86	−.86 −3.66	.42 .006
Step three
Age	−0.34	−1.99	0.065	−0.51	−2.97	.01	−.45	−2.36	.05
Disease duration Hoehn and Yahr	0.49 −0.30	3.63 −1.98	0.002 0.07	0.39 −0.22	3.00 −1.43	.01 .17	.39 −.16	2.58 −.99	.04 .35
IFN-γ IL-4	−1.05 0.52	−5.14 2.89	0 .011	−1.09 0.53	−5.99 3.33	0 .006	−1.24 0.52	−5.62 2.76	0.001 0.02