Table 1.
Baseline characteristics of participants (n=2329) according to sleep quality, a single item in the Pittsburgh Sleep Quality Index (PSQI) in the past 7 days
| Sleep quality in past week in the PSQI | |||
|---|---|---|---|
| Baseline characteristics | 0,1=Poor | 2=Fairly good | 3 =Very good |
| Number of participants, n (%) | 414 (17.8) | 1296 (55.6) | 619 (26.6) |
| Age (years), mean (SD) | 60.2 (7.7) | 62.3 (7.9) | 63.0 (7.6) |
| BMI (kg/m2), mean (SD) | 31.9 (7.0) | 30.8 (5.9) | 30.5 (5.9) |
| White, n (%) | 345 (83.3) | 1103 (85.1) | 515 (83.2) |
| Women, n (%) | 289 (69.8) | 776 (59.9) | 344 (55.6) |
| Education level (College and above), n (%) | 165 (39.9) | 588 (45.4) | 319 (51.5) |
| Currently work for pay, n (%) | 178 (43) | 583 (45) | 286 (46) |
| Tobacco smoking pack-years, mean (SD) | 8.8 (18.2) | 8.6 (16.9) | 9.4 (18.5) |
| Level of fatigue, median (interquartile range) | 5 (3,7) | 3 (2,5) | 2 (1, 3) |
| Charlson comorbidity index, mean (SD) | 0.7 (1.3) | 0.5 (1.0) | 0.4 (0.8) |
| High depressive symptoms1 (yes), n (%) | 127 (30.7) | 121 (9.3) | 12 (3.4) |
| WOMAC2 pain score, median (interquartile range) | 3 (1, 7) | 2 (0, 5) | 1 (0, 3) |
| Prescription use of NSAID3s, n (%) | 76 (18.5) | 168 (13.0) | 73 (11.8) |
| Widespread pain (presence), n (%) | 235 (56.8) | 558 (43.1) | 163 (26.3) |
| Prevalence of radiographic knee OA4 (yes), n (%) | 444 (56.4) | 1414 (56.2) | 636 (52.8) |
1
High depressive symptom was defined based on the CES-D ≥16 (reference 22)
2
The Western Ontario and McMaster Universities Osteoarthritis Index
3
Nonsteroidal anti-inflammatory drugs
4
Radiographic knee OA was defined as a Kallgren Lawrence grade ≥2 present in a knee.