Table 3.
Baseline demographic characteristics of cohort, overall and by percent time in slow wave sleep (SWS) quartiles (Q1-Q4).
| Characteristic | OVERALL | Q1: <4.1 | Q2: 4.1 TO 10.2 | Q3: 10.2 TO 16.9 | Q4: >16.9 | P VALUE |
|---|---|---|---|---|---|---|
| Mean± SD | (N= 784) | (N= 195) | (N= 197) | (N= 192) | (N= 200) | |
| Age (years) | 75.1 ± 4.9 | 76.5 ± 5.5 | 74.6± 4.9 | 74.6 ± 4.3 | 74.8 ± 4.5 | 0.0001 |
| BMI (kg/m2) | 26.4 ± 3.4 | 27.0± 3.7 | 26.3± 3.0 | 26.5 ± 3.6 | 25.9± 3.3 | 0.015 |
| Neck circumference (cm) | 39.0 ± 2.7 | 39.4 ± 2.6 | 38.9 ± 2.6 | 38.9 ± 2.7 | 38.5 ± 2.7 | 0.012 |
| Waist circumference (cm) | 97.3 ± 10.0 | 98.8 ± 10.3 | 97.1± 8.7 | 97.0 ± 10.4 | 96.4 ± 10.2 | 0.096 |
| Hip circumference (cm) | 101.9 ± 8.3 | 102.9 ± 7.9 | 101.6 ± 7.2 | 101.9 ± 10.2 | 101.1 ± 7.5 | 0.162 |
| Baseline SBP | 121.0 ± 10.6 | 121.8 ± 10.5 | 120.9 ± 10.1 | 120.9 ± 10.9 | 120.3 ± 10.9 | 0.569 |
| Baseline DBP | 67.5 ± 7.7 | 67.3 ± 7.8 | 67.7 ± 7.5 | 67.5 ± 7.8 | 67.5 ± 7.9 | 0.962 |
| Follow-up SBP | 118.7 ± 16.3 | 121.0 ± 16.5 | 118.2 ± 14.8 | 116.6 ± 16.6 | 118.9 ± 16.8 | 0.061 |
| Follow-up DBP | 68.1 ± 9.7 | 68.1 ± 9.8 | 68.6 ± 9.5 | 67.0 ± 9.5 | 68.4 ± 10.0 | 0.371 |
| PASE score | 160.8 ± 71.3 | 162.6 ± 71.9 | 152.5 ± 69.6 | 164.3± 71.6 | 163.9 ± 72.2 | 0.305 |
| Respiratory disturbance index (RDI) | 10.0 ± 12.0 | 13.3 ± 15.3 | 9.8 ± 10.9 | 9.4 ± 11.6 | 7.7 ± 8.8 | 0.006† |
| Overall arousal index | 22.9 ± 11.3 | 26.5 ± 13.5 | 22.7 ± 11.1 | 21.8 ± 9.5 | 20.6 ± 9.8 | <.0001† |
| Central apnea index | 1.5 ± 4.5 | 1.7 ± 6.1 | 1.5 ± 4.0 | 1.2 ± 2.9 | 1.4 ± 4.5 | 0.813† |
| Sleep efficiency | 75.9 ± 11.7 | 72.4 ± 12.5 | 76.1 ± 11.6 | 76.3 ± 11.9 | 78.7 ± 10.1 | <.0001 |
| Total sleep duration (minutes) | 364.2 ± 66.4 | 350.2 ± 77.0 | 370.0 ± 58.7 | 368.6 ± 66.8 | 367.7 ± 60.4 | 0.009 |
| Wake after sleep onset (minutes) | 106.3 ± 63.1 | 122.2 ± 64.0 | 109.5 ± 70.6 | 102.1 ± 57.5 | 91.6 ± 55.4 | <.0001 |
| Time in SWS (minutes) | 41.4 ± 31.8 | 6.0 + 5.0 | 25.7 +7.8 | 49.4 +11.2 | 83.7 +20.7 | <.0001 |
| Percentages (%) | ||||||
| Non-Caucasian race | 68 (8.7) | 22 (11.3) | 16 (8.1) | 22 (11.5) | 8 (4) | 0.027 |
| Current smoker | 22 (2.8) | 9 (4.6) | 4 (2.0) | 1 (0.5) | 8 (4) | 0.058 |
| Has ≥1 alcoholic drink/week* | 432 (55.4) | 104 (53.9) | 108 (55.4) | 105 (54.7) | 115 (57.5) | 0.902 |
| Use of sleep medication | 72 (9.2) | 19 (9.7) | 21 (10.7) | 18 (9.4) | 14 (7) | 0.628 |
| Diabetes mellitus | 45 (5.7) | 13 (6.7) | 9 (4.6) | 13 (6.8) | 10 (5.0) | 0.708 |
| History of cardiovascular disease | 154 (19.7) | 39 (20.1) | 40 (20.3) | 33 (17.3) | 42 (21.0) | 0.80 |
| Prehypertensive at baseline | 477 (60.8) | 127 (65.1) | 118 (59.9) | 112 (58.3) | 120 (60.0) | 0.543 |
| Self-rating of health: excellent or good | 723 (932.3) | 188(96.4) | 183 (92.9) | 168 (88.0) | 184 (92.0) | 0.0197 |
| GDS Score ≥6 | 34 (4.3) | 9 (4.6) | 6 (3.0) | 8 (4.17) | 11 (5.5) | 0.684 |
| RDI≥5 | 423 (54.0) | 119 (61.0) | 111 (56.3) | 94 (49.0) | 99 (49.5) | 0.048 |
| Sleep Time Pao2 <80% | 0.05 ± 0.3 | 0.1 ± 0.5 | 0.02 ± 0.15 | 0.04 ± 0.21 | 0.04 ± 0.24 | 0.013† |
| ACEI/ARB use at follow-up | 75 (9.6) | 29 (14.9) | 14 (7.1) | 15 (7.8) | 17 (8.5) | 0.034 |
| Diuretic use at follow-up | 48 (6.1) | 16 (8.2) | 9 (4.6) | 16 (8.3) | 7 (3.5) | 0.097 |
| Beta blocker use at follow-up | 79 (10.1) | 21 (10.8) | 17 (8.6) | 23 (12.0) | 18 (9) | 0.66 |
| Calcium channel blocker use at follow-up | 17 (2.2) | 5 (2.6) | 6 (3.1) | 2 (1.0) | 4 (2.0) | 0.57 |
BMI: body mass index, PASE: physical activity score in the elderly, REM: rapid eye movement sleep, SBP: systolic blood pressure, DBP: diastolic blood pressure. RDI: respiratory disturbance index; GDS: Geriatric Depression Scale; Pao2: partial pressure of oxygen in arterial blood. ACEI: Angiotensin converting enzyme inhibitor; ARB: Angiotensin II receptor blocker.
*
Further categorization of alcoholic drinks per week 0, <1, 1-2, 3-5, 6-13, or 14+ did not significantly change results. Bold P values denote P<0.05.
†
denotes use of Kuskal-Wallis statistic due to non-normal distributions.