Table 1

Characteristics of study participants in percentages or means and SD, by diagnosis

Means (SD) and percentagesn
(155)
SCI
(n=60)
MCI
(n=63)
AD dementia
(n=32)
P value (X2/ANOVA)
Age (years, ANOVA)15560.2 (6.46)62.6 (7.92)67.9 (8.29)<0.001***
Education (years, ANOVA)15514.4 (3.24)14.0 (3.50)13.4 (3.07)0.380
Female (%, X2)15561.754.068.80.360
Awakening time (hh:mm, ANOVA)15507:1106:5807:180.360
Stress measures
 Perceived Stress Scale (__ /40, ANOVA)14517.6 (6.25)19.0 (8.06)18.0 (7.41)0.267
 Cortisol
 Awakening cortisol (t1) (nmol/L, ANOVA)1558.2 (4.48)9.1 (5.24)11.0 (5.78)0.042*
 Bedtime cortisol (t6) (nmol/L, ANOVA)1552.0 (2.72)2.7 (4.43)2.3 (3.60)0.541
 Cortisol awakening response (ANOVA)1550.69 (1.41)0.60 (1.18)0.27 (1.26)0.326
 Daily cortisol output (ANOVA)15575.5 (46.05)91.0 (79.22)78.3 (33.30)0.333
 Cortisol AM/PM ratio (t1/t6) (ANOVA)1559.45 (8.75)7.39 (5.39)10.02 (7.99)0.166
CSF biomarkers
 Aβ42 (ng/L, ANOVA)135867.4 (172.68)713.6 (229.81)426.7 (107.69)<0.001***
 Aβ42 ≤550 ng/L (%, X2)1353.828.887.1<0.001***
 T-Tau (ng/L, ANOVA)135279.5 (112.73)321.8 (183.48)612.2 (266.71)<0.001***
 T-Tau >400 ng/L (%, X2)13513.523.183.9<0.001***
 P-Tau (ng/L, ANOVA)13541.7 (14.24)45.4 (21.37)72.5 (28.84)<0.001***
 P-Tau >80 ng/L (%, X2)1353.87.729.00.001**
Cognition
 Overall cognition (mean z-score, ANOVA)125−0.28 (0.86)−0.91 (0.84)−1.29 (0.89)<0.001***
 Memory (mean z-score, ANOVA)134−0.05 (0.78)−1.46 (1.18)−2.77 (0.88)<0.001***
 Processing speed (mean z-score, ANOVA)124−0.26 (1.14)−1.00 (1.26)−1.52 (1.02)<0.001***
 Working memory (mean z-score, ANOVA)110−0.25 (0.82)−0.83 (1.11)−1.17 (0.40)<0.001***
 Perceptual reasoning (mean z-score, ANOVA)1270.05 (0.84)−0.61 (0.96)−0.90 (0.91)<0.001**
  • *Significant at p<0.05; **significant at p<0.01, ***significant at p<0.001.

  • AD, Alzheimer’s disease; ANOVA, analysis of variance; MCI, mild cognitive impairment; P-Tau, phosphorylated tau ; SCI, subjective cognitive impairment; T-Tau, total tau.