Table 2.

Association between biological measures and cognitive scores after being adjusted for age and/or motor scores in the control and PD groups

Groups	Dependent variable (independent variable)		IGF‐1 (ng/mL)	cGP (ng/mL)	cGP/IGF‐1 molar ratio	IGFBP‐3 (ng/mL)	IGF‐1/IGFBP‐3 molar ratio
Control	MoCA (Age) n = 23	B	0.005	0.10	0.25	0.001	12.09
		P	0.42	0.006 **	0.01 *	0.35	0.07
	Global Z score (Age) n = 23	B	0.000	0.02	0.07	0.000	1.86
		P	0.99	0.009 **	0.02 *	0.27	0.35
	LMD (Age) n = 23	B	−0.002	0.05	0.16	0.000	3.04
		P	0.59	0.01 *	0.01 *	0.08	0.47
PD‐N	MoCA (Age and MDS‐UPDRS III) n = 70	B	−0.007	−0.04	−0.16	0.001	−8.57
		P	0.24	0.52	0.44	0.22	0.07
	Global Z score (Age and MDS‐UPDRS III) n = 67	B	−0.001	−0.01	−0.03	0.00	0.02
		P	0.70	0.32	0.46	0.70	0.98
	LMD (Age and MDS‐UPDRS III) n = 67	B	0.00	−0.02	−0.11	0.00	1.55
		P	0.65	0.35	0.18	0.52	0.43
PD‐MCI	MoCA (Age and MDS‐UPDRS III) n = 63	B	0.00	−0.11	−0.23	0.00	−3.30
		P	0.99	0.14	0.40	0.78	0.63
	Global Z score (Age and MDS‐UPDRS III) n = 61	B	0.00	−0.003	−0.001	0.00	0.01
		P	0.71	0.82	0.98	0.36	0.99
	LMD (Age and MDS‐UPDRS III) n = 61	B	0.00	0.02	0.05	0.00	1.71
		P	0.81	0.29	0.36	0.33	0.38
PD‐D	MoCA (Age and MDS‐UPDRS III) n = 22	B	0.008	0.44	0.12	0.001	−0.09
		P	0.71	0.15	0.59	0.29	0.63

PD‐N, Parkinson disease with normal cognitive function; PD‐MCI, Parkinson disease with mild cognitive impairment; PD‐D, Parkinson disease with dementia; MDS‐UPDRS III, Movement Disorder Society—Unified Parkinson's Disease Rating Scale III; MoCA, Montreal Cognitive Assessment; LMD, Learning Memory Domain scores; Global Z score, global measure of cognitive function derived from comprehensive neuropsychological testing; B, unstandardized co‐efficiency.

^* P < 0.05.

^** P < 0.01.