Table 2 Demographic and data, GDNF protein and mRNA expression levels among four groups.

Age (years)

62.44 ± 10.34

61.10 ± 6.58

58.70 ± 9.92

57.58 ± 5.28

2.76

0.044^a

Gender (male/female)

20/19

25/17

9/31

22/16

14.32

0.003^b

Education level (years)

8.15 ± 4.36

9.43 ± 4.01

9.40 ± 4.77

8.24 ± 2.56

1.22

0.305^a

Active smokers n (%)

16 (41.0%)

21 (50.0%)

9 (22.5%)

—

6.80

0.033^b

Alcohol consumption n (%)

9 (23.1%)

16 (38.1%)

16 (40.0%)

—

3.03

0.219

HAMD

16.00 ± 5.45

3.36 ± 2.02

19.45 ± 4.75

2.18 ± 1.98

203.32

<0.001^a

MMSE

22.64 ± 6.80

27.00 ± 2.45

27.08 ± 1.45

28.47 ± 1.45

28.46

<0.001^c

NIHSS

5.64 ± 4.69

2.64 ± 2.90

—

—

−3.44

0.001^d

GDNF Protein level (ng/ml)^†

0.46 ± 0.21

0.40 ± 0.18

0.26 ± 0.09

0.40 ± 0.21

22.70

<0.001^c

GDNF mRNA expression level^‡

0.19 ± 0.15

0.15 ± 0.13

0.05 ± 0.05

1.00 ± 1.60

29.44

<0.001^c