Table 1.
Characteristics of participants included in the original Wisconsin Sleep Cohort (original sample), of those considered as the baseline for this study and of those finally followed
| Baseline characteristics | Original WSC | Baseline for the present study | Followed |
|---|---|---|---|
| Total, n | 1538 | 820 | 424 |
| Sociodemographic, lifestyle and health | |||
| Age (years), median (IQR) | 60 (53, 67) | 62 (56, 67) | 60 (54, 65) |
| Female, n (%) | 701 (44.8) | 369 (45.0) | 194 (45.8) |
| Lower educational levela, n (%) | 386 (25.1) | 198 (24.1) | 103 (24.3) |
| Married, n (%) | 1062 (69.1) | 576 (70.2) | 300 (70.8) |
| Current smoker, n (%) | 187 (12.2) | 65 (7.9) | 36 (8.5) |
| Alcohol intake (drinks/week), median (IQR) | 2 (0, 6) | 2 (0, 5) | 2 (0, 5) |
| BMI (kg/m2), median (IQR) | 30 (26, 35) | 30 (26, 35) | 30 (26, 35) |
| Excellent or very good self-rated health, n (%) | 521 (57.1)b | 482 (58.8) | 269 (63.4) |
| Depression or antidepressant use, n (%) | 425 (27.6) | 220 (26.8) | 111 (26.2) |
| CPAP use, n (%) | 93 (6.0) | 61 (7.4) | 14 (3.3) |
| Physical activity (MET-minutes/week), n | 915 | 820 | 424 |
| <500 | 285 (31.1) | 255 (31.1) | 124 (29.2) |
| 500 to 1500 | 287 (31.4) | 257 (31.3) | 144 (34.0) |
| >1500 | 343 (37.5) | 308 (37.6) | 156 (36.8) |
| Median (IQR) | 996 (320, 2165) | 1008 (336, 2091) | 1041 (420, 1997) |
| Sleep measures (PSG), n | 1564 | 820 | 424 |
| Apnea-hypopnea index, median (IQR) | 7.8 (3.7, 18.0) | 8.9 (3.7, 18.2) | 9.5 (3.1, 18.9) |
| TST (hours/night), median (IQR) | 6.0 (5.3, 6.8) | 6.0 (5.4, 6.7) | 6.2 (5.6, 6.8) |
| SOL (minutes), median (IQR) | 10 (5, 20) | 8 (4, 17) | 7 (3.5, 13) |
| WASO (minutes), median (IQR) | 68 (48, 103) | 66 (40, 98) | 60 (37, 91) |
| Sleep efficiency (%), median (IQR) | 81 (72, 88) | 81 (74, 88) | 83 (76, 89) |
| % of TST in N1, median (IQR) | 9 (6, 14) | 9 (6, 14) | 9 (6, 14) |
| % of TST in N2, median (IQR) | 65 (58, 71) | 63 (57, 70) | 63 (56, 69) |
| % of TST in N3 (phases 3 and 4), median (IQR) | 7 (2, 14) | 9 (4, 15) | 9 (4, 16) |
| % of TST in REM, median (IQR) | 16 (11, 20) | 16 (13, 20) | 17 (13, 20) |
| TST < 6 hours, n (%) | 728 (47.3) | 400 (48.8) | 192 (45.3) |
| SOL >10 minutes, n (%) | 756 (49.2) | 339 (41.3) | 139 (32.8) |
| WASO > 60 minutes, n (%) | 880 (57.2) | 455 (55.5) | 212 (50.0) |
| Sleep efficiency <80%, n (%) | 730 (47.5) | 368 (44.9) | 166 (39.2) |
| Percentage of TST in N1 <10%, n (%) | 837 (54.4) | 446 (54.4) | 240 (56.6) |
| Percentage of TST in N2 <65%, n (%) | 750 (48.8) | 464 (46.6) | 254 (59.9) |
| Percentage of TST in N3 <10%, n (%) | 971 (63.1) | 467 (57.0) | 238 (56.1) |
| Percentage of TST in REM <15%, n (%) | 702 (45.6) | 347 (42.3) | 158 (37.3) |
IQR, interquartile range; MET, metabolic equivalent; SF-36, Short-form quality of life instrument.
aUp to high school.
bAvailable for 913 participants.