Table 1. Participant Characteristics and Between-Group Differences.
| Characteristic | Mean (SD) | P value for between-group differencesa | |
|---|---|---|---|
| Without SDB (n = 31) | With SDB (n = 96) | ||
| Demographic | |||
| Age, y | 69.19 (3.53) | 69.00 (3.98) | .81 |
| Female, No. (%) | 24 (77.4) | 56 (58.3) | .06 |
| Education, y | 13.45 (2.94) | 12.90 (3.12) | .38 |
| Geriatric Depression Scale score | 1.55 (1.89) | 1.21 (1.70) | .35 |
| State-Trait Inventory form B total score | 36.13 (7.35) | 34.05 (6.88) | .15 |
| BMI | 24.77 (5.07) | 26.73 (3.92) | .03 |
| Current sleep medication use, No. (%)b | 2 (6.45) | 10 (10.42) | .51 |
| Florbetapir standard uptake value ratioc | 0.91 (0.13) | 0.99 (0.23) | .07 |
| Amyloid positive, % | 10 | 25 | .08 |
| Carrying APOE4, No. (%) | 9 (29.03) | 26 (27.08) | .83 |
| Sleep | |||
| Pittsburgh Sleep Quality Index score | 4.39 (2.67) | 5.17 (3.16) | .22 |
| Epworth Sleepiness Scale score | 4.77 (3.04) | 5.22 (3.45) | .52 |
| Total sleep time, min | 358.63 (59.13) | 362.81 (67.62) | .76 |
| Sleep efficiency, % | 76.39 (10.24) | 77.36 (9.89) | .64 |
| Sleep onset latency, min | 18.73 (12.41) | 21.12 (12.49) | .35 |
| Apnea-hypopnea index events, No. per h | 9.63 (3.91) | 30.54 (13.26) | <.001 |
| Fragmentation composite score | −0.68 (0.41) | 0.22 (0.81) | <.001 |
| Respiratory arousals index, No. per h | 7.15 (3.34) | 25.28 (11.30) | <.001 |
| Shifts to non–rapid eye movement sleep stage 1, No. per h | 5.81 (2.08) | 8.39 (3.53) | .001 |
| Awakenings, No. per h | 3.29 (1.12) | 4.11 (1.72) | .02 |
| Hypoxia composite scored | −0.44 (0.39) | 0.15 (0.85) | <.001 |
| Oxygen desaturation ≥3% index, No. per h | 5.50 (3.96) | 16.50 (11.21) | <.001 |
| Total sleep time with oxygen saturation ≤90%, % | 0.50 (1.08) | 2.88 (9.69) | .18 |
| Minimal oxygen saturation, % | 88.27 (3.82) | 85.89 (5.05) | .02 |
| Cognition scores | |||
| Mini-Mental State Examination | 28.81 (1.08) | 29.06 (1.04) | .24 |
| Mattis Dementia Rating Scale | 140.61 (2.89) | 141.17 (2.64) | .32 |
| Processing speed composite | 0.05 (0.85) | −0.02 (0.70) | .66 |
| Attention composite | −0.04 (0.66) | 0.04 (0.63) | .58 |
| Executive functioning composite | 0.12 (0.70) | −0.04 (0.67) | .26 |
| Working memory composite | 0.04 (1.03) | −0.03 (0.85) | .72 |
| Episodic memory composite | 0.16 (0.81) | −0.05 (0.69) | .17 |
| Cognitive Difficulties Scale | 33.84 (14.27) | 34.18 (15.59) | .91 |
Abbreviations: APOE, apolipoprotein E; BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); SDB, sleep-disordered breathing.
Between-group differences were assessed using t tests for continuous variables and χ2 statistics for categorical variables. Statistical significance was set to P < .05.
Use of sleep medication on a regular basis (>1/week), excluding phytotherapy and homeopathy.
Thirty control participants with valid florbetapir–positron emission tomography scan. The threshold for amyloid positivity was defined as more than 0.99 and corresponded to the 99.9th percentile of the neocortical standard uptake value ratio distribution among 45 healthy young individuals younger than 40 years.
Thirty participants without SDB and 88 participants with SDB with valid oxygen saturation data.