Table 4 Comparisons of demographic and clinical characteristics among Parkinson’s disease patients categorized by coffee drinking status (Non-coffee drinker, Coffee drinker - 1 cup a day, Coffee drinker - more than 1 cup a day [median = 1])

 Age (years)

68.79 ± 8.24

66.52 ± 8.97

62.52 ± 10.22

<  0.001

<  0.001

 Sex (female:male)

53:27

48:51

36:69

<  0.001

<  0.001

 Age at symptom onset (years)

67.00 ± 8.15

64.85 ± 8.94

60.80 ± 10.56

<  0.001

<  0.001

 Disease duration (months)

22.04 ± 22.65

20.40 ± 19.16

20.93 ± 27.00

NS

NS

 Formal education (years)

5.77 ± 4.28

8.15 ± 4.86

8.92 ± 5.53

<  0.001

<  0.001

 Modified H-Y stage

1.89 ± 0.84

1.82 ± 0.72

1.66 ± 0.82

NS

0.028

NS*

 UPDRS motor score

22.84 ± 12.04

20.9 ± 9.6

17.9 ± 9.9

0.006

0.002

NS*

 UPDRS ADL score

8.22 ± 6.60

7.0 ± 5.5

6.8 ± 5.2

NS

NS

 Tremor

3.64 ± 2.90

2.56 ± 2.37

2.40 ± 2.07

0.003

0.001

0.002*†

 Rest tremor (Item 20)

2.41 ± 2.23

1.77 ± 1.43

1.41 ± 1.73

0.001

<  0.001

0.002*†

 Action tremor (Item 21)

1.23 ± 1.45

1.30 ± 1.40

0.90 ± 1.20

0.076

0.074

NS*

 Bradykinesia

10.83 ± 6.28

9.61 ± 5.72

8.89 ± 5.22

0.037

0.012

NS*

 Rigidity

4.92 ± 2.99

5.13 ± 2.96

4.28 ± 2.75

NS

NS

 Gait and Posture

1.16 ± 1.27

0.90 ± 1.07

0.68 ± 1.27

0.015

0.004

NS*

 Tremor score (Jankovic)

0.60 ± 0.41

0.45 ± 0.35

0.43 ± 0.28

0.004

0.001

0.003*†

 PIGD score (Jankovic)

0.47 ± 0.52

0.43 ± 0.47

0.38 ± 0.50

NS

NS

 Tremor score (Kang)

0.89 ± 0.72

0.64 ± 0.59

0.60 ± 0.50

0.003

0.001

0.002*†

 Akinetic-Rigid score (Kang)

1.04 ± 0.60

0.95 ± 0.52

0.85 ± 0.48

NS

0.018

NS*

 MMSE

24.38 ± 4.00

25.3 ± 3.7

26.2 ± 3.7

0.009

<  0.001

NS**

 MoCA

22.31 ± 5.04

22.7 ± 5.2

25.1 ± 3.6

0.001

0.001

NS**

 BDI

15.47 ± 11.51

11.66 ± 7.90

11.00 ± 8.84

0.006

0.003

NS**

 Total NMSS score

65.72 ± 46.24

48.25 ± 47.25

50.48 ± 45.88

NS

NS