Table 1.
Demographic characteristics, actigraphic variables, and plasma Alzheimer’s disease-related biomarkers in the whole study sample (n = 92), as well as stratified by sex
| Whole sample (n = 92) | Females (n = 47) | Males (n = 45) | P value* | |
|---|---|---|---|---|
| Demographic characteristics | ||||
| Age, years | 59.85 ± 13.77 [30–85] | 58.15 ± 13.48 [30–80] | 61.62 ± 14.01 [31–85] | 0.24 |
| Education, years | 14.52 ± 1.99 [10–20] | 14.34 ± 2.08 [10–20] | 14.71 ± 1.89 [10–20] | 0.24 |
| Ethnicity | Caucasian | Caucasian | Caucasian | |
| Right-handed, n (%) | 92 (100) | 47 (100) | 45 (100) | |
| Body mass index, Kg/m² | 24.45 ± 2.95 [17.56–31.71] | 23.92 ± 3.12 [17.56–31.71] | 25.01 ± 2.68 [19.71–30.04] | 0.08 |
| APOE ε4 carriers, n (%) | 33 (36) | 14 (30) | 19 (42) | 0.28 |
| One allele, n (%) | 28 (30) | 12 (26) | 16 (35) | 0.37 |
| Two alleles, n (%) | 5 (6) | 2 (4) | 3 (7) | 0.67 |
| Mini-Mental State Examination, score | 29.00 ± 1.15 [26–30] | 29.19 ± 1.01 [26–30] | 28.80 ± 1.25 [26–30] | 0.14 |
| Hamilton Depression Rating Scale, score | 2.18 ± 2.47 [0–12] | 2.36 ± 2.75 [0–12] | 2.00 ± 2.14 [0–11] | 0.82 |
| Groningen Sleep Quality Scale, score | 2.87 ± 3.46 [0–14] | 3.68 ± 3.60 [0–13] | 2.10 ± 3.17 [0–14] | 0.02 |
| Self-reported sleep apnea symptoms, score | 0.70 ± 0.86 [0–3] | 0.80 ± 0.97 [0–3] | 0.60 ± 0.73 [0–3] | 0.47 |
| Self-reported use of sleep medication, n (%)a | 7 (8) | 5 (11) | 2 (4) | 0.10 |
| Actigraphic variables | ||||
| Recording duration, days | 9.80 ± 0.73 [7.07–12.07] | 9.71 ± 0.59 [7.80–11.55] | 9.89 ± 0.85 [7.07–12.07] | 0.52 |
| Actigraphic device wear ratio | 1.00 ± 0.004 [0.97–1.00] | 1.00 ± 0.005 [0.97–1.00] | 1.00 ± 0.003 [0.99–1.00] | 0.54 |
| Intradaily variability | 0.53 ± 0.16 [0.27–1.08] | 0.48 ± 0.12 [0.27–0.77] | 0.58 ± 0.18 [0.33–1.08] | 0.005 |
| Interdaily stability | 0.63 ± 0.09 [0.43–0.83] | 0.65 ± 0.09 [0.44–0.83] | 0.61 ± 0.08 [0.43–0.77] | 0.07 |
| Plasma AD biomarkers | ||||
| NfL (pg/ml) | 18.6 ± 7.32 [6.56–43.4] | 18 ± 6.77 [6.78–34.6] | 19.2 ± 7.88 [6.56–43.4] | 0.49 |
| GFAP (pg/ml) | 153 ± 60.2 [53.8–389] | 156 ± 60.3 [53.8–336] | 149 ± 60.6 [75.3–389] | 0.37 |
| Aβ40 (pg/ml) | 92.1 ± 11.3 [66.3–125] | 91.4 ± 9.18 [73.7–119] | 92.9 ± 13.2 [66.3–125] | 0.53 |
| Aβ42 (pg/ml) | 8.35 ± 1.30 [3.32–11] | 8.36 ± 1.24 [5.98–11.02] | 8.34 ± 1.37 [3.32–10.8] | 0.94 |
| Aβ42/40 ratio | 0.09 ± 0.01 [0.05–0.12] | 0.09 ± 0.01 [0.06–0.12] | 0.09 ± 0.01 [0.05–0.12] | 0.62 |
| t-tau (pg/ml)b | 2.63 ± 0.87 [0.75–7.58] | 2.68 ± 0.71 [0.75–4.01] | 2.58 ± 1.02 [1.39–7.58] | 0.18 |
| p-tau181 (pg/ml)b | 1.66 ± 0.75 [0.80–6.44] | 1.48 ± 0.55 [0.80–3.15] | 1.85 ± 0.89 [0.91–6.44] | 0.004 |
| p-tau231 (pg/ml) | 8.39 ± 3.80 [3.29–28.9] | 7.75 ± 2.59 [3.81–16.3] | 9.07 ± 4.68 [3.29–28.9] | 0.33 |
a data missing for n = 10, b data missing for n = 6
*P values related to statistical differences between female and male participants were computed using χ² or Fisher’s exact tests for categorical variables and Student’s t or Mann-Whitney U test for continuous variables, depending on the normality of the distribution of the variables. Abbreviations: Aβ42/40 = amyloid-beta42/40 ratio, APOE = Apolipoprotein E, GFAP = glial fibrillary acidic protein, NfL = neurofilament light chain, t-tau = total tau, p-tau181 = tau phosphorylated at threonine 181, p-tau231 = tau phosphorylated at threonine 231