Table 1.
Characteristics by Case-Control Status
| All | Control | Case | ||
|---|---|---|---|---|
| Characteristic | (N= 575) | (N= 290) | (N= 285) | P-value1 |
| Age, y | 76.81 ± 5.38 | 76.27 ± 5.35 | 77.36 ± 5.36 | 0.01 |
| Not of Caucasian race | 38 (6.61) | 20 (6.9) | 18 (6.32) | 0.78 |
| Body mass index, kg/m2 | 28.01 ± 3.89 | 27.93 ± 3.89 | 28.08 ± 3.88 | 0.64 |
| Depression, GDS score (range 0 to 15) | 1.94 ± 2.19 | 1.83 ± 2.26 | 2.05 ± 2.12 | 0.03 |
| History of self-reported medical conditions: | ||||
| Diabetes | 79 (13.76) | 30 (10.34) | 49 (17.25) | 0.02 |
| Stroke or TIA | 70 (12.2) | 23 (7.93) | 47 (16.55) | 0.002 |
| Coronary heart disease2 | 218 (38.11) | 87 (30.1) | 131 (46.29) | <.0001 |
| COPD | 32 (5.57) | 12 (4.14) | 20 (7.04) | 0.13 |
| Hypertension | 308 (53.66) | 135 (46.55) | 173 (60.92) | 0.0006 |
| PVD | 79 (14.18) | 26 (9.22) | 53 (19.27) | 0.0007 |
| Diastolic blood pressure, mmHg | 68.08 ± 9.35 | 68.3 ± 9.32 | 67.84 ± 9.39 | 0.56 |
| Systolic blood pressure, mmHg | 127.77 ± 16.83 | 126.36 ± 14.6 | 129.22 ± 18.75 | 0.04 |
| Current antidepressant use | 56 (9.74) | 29 (10) | 27 (9.47) | 0.83 |
| Current prescription sleep medication use | 11 (1.91) | 5 (1.72) | 6 (2.11) | 0.74 |
| Current use of beta blockers | 184 (32) | 71 (24.48) | 113 (39.65) | 0.0001 |
| Smoking | ||||
| Never | 229 (39.9) | 121 (41.72) | 108 (38.03) | 0.66 |
| Past | 333 (58.01) | 163 (56.21) | 170 (59.86) | |
| Current | 12 (2.09) | 6 (2.07) | 6 (2.11) | |
| Alcohol intake (drinks/week) | ||||
| 0–2 | 349 (61.01) | 169 (58.48) | 180 (63.6) | 0.26 |
| 3–13 | 184 (32.17) | 96 (33.22) | 88 (31.1) | |
| 14+ | 39 (6.82) | 24 (8.3) | 15 (5.3) | |
| PASE physical activity score | 144.19 ± 71.68 | 142.6 ± 66.38 | 145.81 ± 76.8 | 0.59 |
| Apnea-hypopnea index | 25.71 ± 14.67 | 25.19 ± 14.18 | 26.24 ± 15.16 | 0.47 |
| Obstructive apnea index | 8.25 ± 10.00 | 8.00 ± 10.12 | 8.51 ± 9.90 | 0.27 |
| Central apnea index | 2.52 ±6.31 | 2.69 ± 6.42 | 2.34 ± 6.20 | 0.86 |
| Oxygen desaturation index | 30.09 ±15.53 | 29.46 ± 15.05 | 30.74 ± 16.01 | 0.35 |
| Percent of sleep time with SaO2<90% ≥10% | 107 (18.61) | 44 (15.17) | 63 (22.11) | 0.03 |
| Sleep efficiency, % | 75.05 ± 11.77 | 75.91 ± 11.39 | 74.16 ± 12.09 | 0.09 |
| Arousal Index | 26.96 ± 12.28 | 26.55 ± 11.36 | 27.38 ± 13.15 | 0.42 |
| WASO, min | 120.96 ± 66.38 | 118.32 ± 66.71 | 123.65 ± 66.05 | 0.34 |
| Pittsburgh sleep quality index (range 0–21) | 5.87 ± 3.35 | 5.62 ± 3.11 | 6.11 ± 3.57 | 0.08 |
| Pittsburgh sleep quality index >5 | 273 (47.56) | 133 (45.86) | 140 (49.3) | 0.41 |
| Epworth sleepiness scale (range 0–24) | 6.5 ± 3.95 | 6.19 ± 3.7 | 6.82 ± 4.17 | 0.05 |
| Epworth sleepiness scale>10 | 89 (15.48) | 41 (14.14) | 48 (16.84) | 0.37 |
GDS, Geriatric Depression Scale; TIA, Transient ischemic attack; COPD, Chronic obstructive pulmonary disease; PVD, peripheral vascular disease; PASE score, physical activity score of elderly; SaO2,oxygen saturation; WASO, wake after sleep onset.
Results shown as mean ± SD or n(percent).
P-values for continuous variables are from a t-test for normally distributed variables, a Wilcoxon rank-sum test for skewed data GDS score, apnea-hypopnea index, central apnea index, obstructive apnea index, oxygen desaturation index. P-values for categorical data from a chi-square test.
Self reported history of coronary heart disease includes myocardial infarction, angina, congestive heart failure, bypass surgery, angioplasty or pacemaker placement.