Table 1.
Population characteristics of participants according to trajectories of sleep duration
| Sleep duration trajectory group | ||||||
|---|---|---|---|---|---|---|
| Persistent sleep duration of 5 h | Persistent sleep duration of 6 h | Persistent sleep duration of 7 h | Persistent sleep duration of 8 h | Increased sleep duration from 6 to 7.5 h | Decreased sleep duration from 8 to 6 h | |
| N | 1,410 | 11,551 | 26,960 | 13,289 | 3,374 | 3,484 |
| Age, years | 55.0 (4.5) | 54.9 (4.5) | 54.8 (4.6) | 54.8 (4.6) | 54.4 (4.6) | 54.6 (4.4) |
| Follow-up, years* | 7.7 (7.4, 7.9) | 7.8 (7.6, 7.9) | 7.8 (7.6, 7.9) | 7.8 (7.6, 7.9) | 7.8 (7.6, 7.9) | 7.8 (7.5, 7.9) |
| Range of follow-up, years | 0.3–8.0 | 0.1–8.0 | 0.1–8.0 | 0.1–8.0 | 0.1–8.0 | 0.1–8.0 |
| White race | 92 | 95 | 98 | 97 | 97 | 94 |
| Currently married | 71 | 77 | 82 | 81 | 78 | 76 |
| Premenopausal | 31 | 32 | 33 | 33 | 33 | 32 |
| Postmenopausal hormone use† | 18 | 22 | 23 | 24 | 24 | 20 |
| Family history of diabetes | 38 | 36 | 34 | 33 | 35 | 36 |
| BMI, kg/m2 | 28.9 (7.1) | 27.8 (6.4) | 26.9 (5.8) | 26.7 (5.8) | 27.9 (6.4) | 27.7 (6.2) |
| AHEI-2010 | 51.9 (10.3) | 51.9 (9.9) | 52.7 (9.9) | 53.0 (10.1) | 52.5 (9.8) | 51.8 (10.1) |
| Alcohol intake, g/day | 3.6 (5.8) | 4.1 (6.2) | 4.7 (6.6) | 4.9 (7.4) | 5.1 (7.5) | 4.0 (6.3) |
| Smoking status | ||||||
| Never | 62 | 65 | 67 | 68 | 60 | 67 |
| Past | 28 | 28 | 28 | 27 | 33 | 27 |
| Current | 10 | 7 | 5 | 5 | 8 | 6 |
| Physical activity, MET h/week | 25.7 (25.7) | 22.5 (21.6) | 21.7 (19.8) | 21.4 (20.2) | 23.7 (24.6) | 20.8 (18.8) |
| Parous | 79 | 83 | 84 | 79 | 81 | 80 |
| Parity‡ | 2.4 (1.1) | 2.3 (1.0) | 2.3 (0.9) | 2.2 (0.9) | 2.3 (1.0) | 2.2 (0.9) |
| Physical examination | 91 | 92 | 94 | 93 | 93 | 91 |
| Medical history | ||||||
| Hypertension | 29 | 27 | 24 | 22 | 29 | 27 |
| High cholesterol | 34 | 33 | 33 | 32 | 35 | 35 |
| Sleep apnea | 5 | 3 | 3 | 3 | 4 | 4 |
| Depression | 15 | 12 | 14 | 17 | 18 | 13 |
| Ever had night shift | 84 | 77 | 70 | 65 | 79 | 70 |
| Lifetime duration of rotating night shift work, years§ | 7.3 (6.2) | 5.8 (5.5) | 4.8 (4.6) | 4.3 (4.2) | 5.8 (5.1) | 5.2 (5.1) |
| Chronotype | ||||||
| Morning type | 54 | 56 | 63 | 63 | 61 | 55 |
| Evening type | 39 | 38 | 32 | 31 | 34 | 39 |
| Neither | 7 | 6 | 5 | 5 | 5 | 5 |
Data except for follow-up years are means (SD) for continuous variables and percentages for categorical variables at baseline (2009). All variables except age and follow-up years are age standardized.
*
Values are median (lower quartile, upper quartile).
†
Calculated among participants with postmenopausal status.
‡
Calculated among parous participants.
§
Calculated among participants who ever had rotating night shift work.