Table 2.
Study sample characteristics by quartile of overall sleep stage transition rate
| Variable | Quartile of overall transition rate (events/h) |
|||
|---|---|---|---|---|
| < 7.76 | 7.77–10.10 | 10.11–13.34 | ≥ 13.35 | |
| Age, years | 61.5 (11.1) | 61.3 (10.8) | 62.6 (10.5) | 65.5 (10.3) |
| Body mass index, kg/m2 | 28.6 (5.6) | 28.3 (5.4) | 28.4 (5.3) | 28.5 (4.9) |
| Sex, % | ||||
| Women | 31.9 | 27.9 | 24.6 | 15.7 |
| Men | 17.3 | 21.8 | 25.5 | 35.5 |
| Race,% | ||||
| White | 24.9 | 24.6 | 25.7 | 24.8 |
| African American | 24.1 | 23.8 | 23.6 | 28.6 |
| Native American | 24.7 | 25.9 | 21.6 | 27.8 |
| Hispanic | 31.4 | 30.0 | 23.8 | 14.8 |
| Other | 23.8 | 31.3 | 20.0 | 25.0 |
| Apnea-hypopnea index, events/h | 6.9 (10.7) | 7.2 (11.2) | 8.2 (11.2) | 12.2 (14.3) |
| Arousal index, events/h | 13.5 (7.7) | 17.0 (8.6) | 19.7 (9.1) | 26.2 (11.7) |
| Total sleep time, minutes | 378.0 (63.0) | 372.3 (60.0) | 361.4 (56.4) | 327.9 (66.8) |
| Wake after sleep onset, minutes | 38.5 (33.7) | 51.0 (36.7) | 64.4 (39.2) | 92.8 (49.7) |
| Sleep efficiency, % | 86.2 (8.7) | 84.0 (8.7) | 81.1 (8.7) | 74.6 (11.2) |
| Sleep architecture | ||||
| Stage 1 sleep, % | 3.5 (2.4) | 4.5 (2.8) | 5.7 (3.4) | 8.4 (5.2) |
| Stage 2 sleep, % | 54.4 (12.1) | 56.3 (11.3) | 57.1 (11.4) | 60.2 (11.4) |
| Slow wave sleep, % | 21.2 (12.3) | 18.7 (11.4) | 17.1 (11.5) | 13.5 (10.9) |
| REM sleep, % | 20.9 (6.0) | 20.5 (5.9) | 20.1 (5.8) | 17.6 (6.6) |
| Restless sleep, % | 18.7 | 23.8 | 27.5 | 30.0 |
| Light sleep, % | 17.8 | 21.8 | 27.5 | 32.9 |
P < 0.0001 for comparisons of age, sex, apnea-hypopnea index, arousal index, total sleep time, wake after sleep onset, sleep efficiency, stage 1 sleep, stage 2 sleep, slow wave sleep, and REM sleep across quartiles of overall transition rate using χ2 and analysis of variance to compare categorical and continuous variables, respectively. Values reported are means (standard deviations) or percentages.