Table 1 Characteristics of subjects involved in the study and levels of plasma biomarkers for Alzheimer’s disease

Age (years)

55.8 ± 2.5

65.0 ± 2.9

73.8 ± 2.8

83.6 ± 2.6

67.3 ± 9.8

Male (n, %)

25 (44.6)

30 (49.2)

31 (63.3)

11 (40.7)

97 (50.3)

Education (n, %)^*

≥ 7 years

44 (78.6)

39 (63.9)

29 (59.2)

5 (18.5)

117 (60.6)

1–6 years

12 (21.4)

22 (36.1)

20 (40.8)

22 (81.5)

76 (39.4)

MMSE

26.9 ± 2.9

26.3 ± 2.6

26.1 ± 1.9

25.5 ± 0.9

26.3 ± 2.6

Haemoglobin (g/L)

147.18 ± 13.42

149.71 ± 13.80

146.64 ± 13.97

141.30 ± 16.19

146.70 ± 14.28

Total cholesterol (mmol/L)

5.74 ± 1.04

5.55 ± 1.23

5.54 ± 0.78

5.42 ± 1.02

5.57 ± 1.03

Triglyceride (mmol/L)

2.01 ± 1.35

1.49 ± 0.77

1.47 ± 0.73

1.46 ± 0.69

1.64 ± 0.99

HDL cholesterol (mmol/L)

1.22 ± 0.26

1.30 ± 0.32

1.27 ± 0.33

1.28 ± 0.29

1.26 ± 0.30

LDL cholesterol (mmol/L)

3.42 ± 0.78

3.41 ± 0.94

3.36 ± 0.66

3.16 ± 0.81

3.36 ± 0.81

Creatinine (μmol/L)^b,c,d,e

63.01 ± 14.73

64.79 ± 11.46

71.67 ± 12.83

72.27 ± 12.34

68.41 ± 20.29

Glucose (mmol/L)

6.62 ± 1.72

6.50 ± 1.68

6.73 ± 1.92

6.91 ± 2.39

6.65 ± 1.79

Aβ42 (pg/mL)^b,c,d,e

6.42 ± 1.98

6.50 ± 1.70

7.36 ± 2.58

8.04 ± 1.98

6.91 ± 2.13

Aβ40 (pg/mL)^b,c,d,e,f

168.57 ± 57.24

161.18 ± 50.86

197.05 ± 62.47

236.06 ± 57.81

182.6 ± 61.9

Aβ42/Aβ40 ratio^c,e

0.039 (0.034, 0.046)

0.038 (0.034, 0.049)

0.037 (0.032, 0.045)

0.035 (0.031, 0.038)

0.038 (0.033, 0.045)

t-tau (pg/mL)

0.80 (0.53, 1.28)

0.67 (0.44, 1.01)

0.86 (0.52, 1.33)

1.06 (0.57, 1.57)

0.78 (0.52, 1.31)

p-tau181 (pg/mL)^a,b,c

0.90 (0.77, 1.29)

1.18 (0.96, 1.77)

1.31 (0.97, 1.93)

1.41 (1.11, 2.58)

1.19 (0.88, 1.76)

p-tau181/t-tau ratio

1.14 (0.77, 1.89)

1.82 (1.17, 2.95)

1.63 (0.89, 2.78)

1.40 (0.93, 2.98)

1.58 (0.90, 2.71)

p-tau181/Aβ42 ratio

0.14 (0.10, 0.22)

0.18 (0.14, 0.27)

0.22 (0.11, 0.33)

0.19 (0.15, 0.30)

0.18 (0.12, 0.28)