Table 3 Worldwide Parkinson’s disease cohorts and IGF-1 levels

Early (< 3.5 years) vs. moderate (> 4 years) PD

37

64 (7)

15F/22M

Levodopa

22 (9) (early)/38 (15) (moderate)

Longitudinal prospective cohort (3.5 years)^a

PD patients in moderate, but not early stages, showed significantly increased baseline IGF-1 levels.

130 (26)/106 (24) p = 0.017

Bernhard et al. [171]

Newly diagnosed idiopathic PD (Germany)

15

69 (8.3)

6F/9M

Drug-naïve

14.30 (5.3)

Cross-sectional cohort^a

IGF-1 level was higher in patients with PD and inversely correlated with the UPDRS-III score (r = − 0.77) among PD patients

IGFBP-3 unchanged

IGF-1 level was not related to motor function in the healthy group

158.4 (40.4)/129.2 (29.1) p = 0.004

Godau et al. [172]

Idiopathic PD (Germany)

18

67 (9)

8F/22M

Levodopa-treated vs. untreated

24.1 (8.5) (treated)/16.2 (4.1) (untreated)

Longitudinal (6 months)^a

IGF-1 was significantly higher in treated PD patients than in controls at all time points (all p < 0.001)

IGF-1 levels were correlated with shorter disease duration (r = 0.56, p < 0.001)

In the patient group, higher IGF-1 levels were correlated with shorter disease duration (r1⁄4 0.56, p1⁄40.001)

In the healthy control group, higher IGF-1 levels were correlated with slightly impaired motor performance (r1⁄40.46, p1⁄40.005)

In the untreated patient group, IGF-1 levels were significantly higher than healthy controls (p < 0.001)

Treatment did not alter GH

149.06 (30.3)/98.96 (23.2)

Godau et al. [173]

PD

38

68 (10)

F and M

–

–

Cross-sectional cohort^a

Serum and CSF IGF-1 and IGFBP levels were higher in PD patients than controls (p < 0.001)

CSF: 5.97 pg/mL (0.93)/4.40 pg/mL (0.58)

Serum: 320.19 (40.86)/207.97 (19.51)

Mashayekhi et al. [174]

PD (75), multiple system atrophy (MSA, 25), and progressive supranuclear palsy (PSP, 16) (Japan)

116

68.1 (1.1)

44F/35M

Drug-naïve vs. levodopa-treated

26.9 (1.8)

Cross-sectional cohort^a

Serum IGF-1 levels tended to be higher in early PD patients than controls

There was a negative correlation between serum IGF-1 levels and age in PD patients and controls

There was no significant correlation between disease duration and serum IGF-1 levels in PD patients

In controls, there was no significant correlation between serum IGF-1 levels and UPDRS part III

In PD and PSP patients, there was a negative correlation between serum IGF-1 levels and UPDRS part III. In early and drug naïve PD patients there was no significant correlation between serum IGF-1 levels and UPDRS part III

IGF-1 serum levels in PD patients with HY stage 2 were significantly higher than those in PD patients with HY stages 3–5

130.3 (14.6)/114.4 (5.9)

Numao et al. [175]

> 3years PD with weight loss (11) vs. PD without weight loss (16)

27

63.5 (8.8)/60.5 (8.6)

6F, 5M/8F, 8M

Levodopa

43.45 (17.26)/37.75 (22.17)

Cross-sectional cohort^a

BMI was lower in all PD patients

Serum leptin levels were lower in all PD patients

Serum GH and IGF-1 levels were higher in all PD patients, mostly in PD with weight loss and without weight loss, respectively

Serum active ghrelin levels were positively correlated with serum IGF-1 levels in the control group (p < 0.05; r = 0.67) but not among PD patients

With weight loss 191.73 (33.84), without weight loss 152.19 (49.62)/144.17 (24.24) (p < 0.05 between PD patients and PD patients with weight loss vs. controls)

Fiszer et al. [176]

PD

25

67.9 (9.4)

5F/20M

Treated, drug not specified

–

Cross-sectional cohort^a

IGF-1 and IGFBP-3 serum levels in PD patients showed no correlation with the duration and severity of the disease

132 (42)/113 (51)

Tuncel et al. [177]

Early PD (< 2 years) (Italy)

65

59.7 (8.3)

26F/39M

Drug-naïve

14.5 (6.7)

2-year follow-up prospective cohort^a

At baseline, serum IGF-1 levels were significantly increased as compared to healthy controls

A positive correlation between IGF-1 levels and a specific executive function (phonological fluency) assessing cognitive flexibility was found

After a 2-year follow-up, IGF-1 levels were positively related to verbal episodic memory, visuoperceptual abilities and attention/executive functions

Low IGF-1 levels at baseline were independently associated to poor performance on specific cognitive tasks assessing verbal episodic memory and executive functions after 2 years

91.6 (34.4)/79.1 (23) (p = 0.019)

Pellecchia et al. [178]

Early PD (< 2 years) (Italy)

37

59.4 (9)

15F/22M

Drug-naïve

14.6 (7.1)

12-month follow-up prospective cohort^a

At baseline, serum IGF-1 levels were moderately increased

Patients at the highest IGF-1 quartile presented higher mean dopaminergic scores (worse outcome)

94.5 (37.5)/79.1 (23) (p < 0.011)

Picillo et al. [179]

Early PD (< 2 years)

405

61.20 (9.7)

141F/264M

Drug-naïve

20.25 (8.93)

5-year follow-up prospective cohort^a

IGF-1 levels were similar in PD and controls

Lower serum IGF-1 levels were associated to poor performances in cognitive tasks assessing executive function, attention and verbal memory

136.6 (56.1)/134.45 (56.13)

Picillo et al. [180]

Meta-analysis covering de novo, drug-naïve idiopathic PD patients

166

–

–

Drug-naïve

–

–

Significantly higher serum IGF-1 levels among de novo, drug-naïve idiopathic PD patients at baseline

Li et al. [181]