Table 2.
Characteristics+ at Phase 7 and sleep duration at Phase 5 by number of hours of sleep at Phase 7 and sleep duration at enrolment among those included and excluded from the study analyses
| Women | N | Hours of Sleep at Phase 7 |
P-value* | ||||
|---|---|---|---|---|---|---|---|
| ≤ 5 h | 6 h | 7 h | 8 h | ≥ 9 h | |||
| Number (%) | 1459 | 148 (10.1) | 494 (33.9) | 550 (37.7) | 242 (16.6) | 25 (1.7) | |
| Age, years | 1459 | 61.2 (0.5) | 60.9 (0.3) | 60.6 (0.3) | 62.3 (0.4) | 60.6 (1.0) | 0.004 |
| Education | |||||||
| Tertiary | 408 | 6.9 | 35.0 | 41.7 | 14.7 | 1.7 | |
| Higher secondary | 326 | 12.2 | 30.7 | 37.4 | 16.0 | 3.7 | 0.004 |
| Secondary | 725 | 11.0 | 34.6 | 35.6 | 17.9 | 0.8 | |
| Occupational position | |||||||
| High | 725 | 6.2 | 34.3 | 42.4 | 16.6 | 0.8 | |
| Intermediate | 326 | 10.1 | 33.7 | 38.6 | 15.3 | 2.3 | 0.002 |
| Low | 408 | 14.5 | 33.6 | 30.7 | 19.7 | 1.5 | |
| Sleep duration at Phase 5 | |||||||
| ≤ 5 h | 139 | 48.9 | 37.4 | 11.5 | 2.2 | 0.0 | |
| 6 h | 470 | 11.7 | 51.7 | 32.1 | 4.3 | 0.2 | |
| 7 h | 571 | 3.0 | 30.7 | 49.7 | 15.9 | 0.7 | < 0.001 |
| 8 h | 253 | 2.0 | 8.3 | 37.9 | 46.6 | 5.1 | |
| ≥ 9 h | 26 | 11.5 | 11.5 | 11.5 | 38.5 | 26.9 | |
| Hours of Sleep at Enrolment to the Whitehall II Cohort |
|||||||
| ≤ 5 h | 6 h | 7 h | 8 h | ≥ 9 h | |||
| Included in the study analyses, N (%) | 1454 | 84 (5.8) | 389 (26.8) | 709 (48.8) | 260 (17.9) | 12 (0.8) | |
| Excluded from the study analyses, N (%) | 1954 | 134 (6.9) | 536 (27.5) | 877 (45.0) | 365 (18.8) | 35 (1.8) | |
| Men | Hours of Sleep at Phase 7 |
||||||
| ≤ 5 h | 6 h | 7 h | 8 h | ≥ 9 h | |||
| Number (%) | 3972 | 269 (6.8) | 1246 (31.4) | 1714 (43.2) | 655 (16.5) | 88 (2.2) | |
| Age, years | 3972 | 60.1 (0.4) | 60.2 (0.2) | 61.0 (0.1) | 62.5 (0.2) | 63.1 (0.6) | < 0.001 |
| Education | |||||||
| Tertiary | 1593 | 6.8 | 31.2 | 43.6 | 15.9 | 2.4 | |
| Higher secondary | 1204 | 6.5 | 31.5 | 43.4 | 16.5 | 2.2 | 0.99 |
| Secondary | 1175 | 7.1 | 31.2 | 42.3 | 17.3 | 2.0 | |
| Occupational position | |||||||
| High | 2238 | 5.3 | 30.7 | 44.2 | 17.7 | 2.2 | |
| Intermediate | 1605 | 8.1 | 31.8 | 42.8 | 15.1 | 2.2 | < 0.001 |
| Low | 129 | 15.5 | 38.0 | 30.2 | 14.0 | 2.3 | |
| Sleep duration at Phase 5 | |||||||
| ≤ 5 h | 259 | 46.3 | 43.6 | 8.9 | 1.2 | 0.0 | |
| 6 h | 1308 | 8.8 | 57.5 | 29.4 | 3.8 | 0.5 | |
| 7 h | 1782 | 1.7 | 19.5 | 61.9 | 16.0 | 0.9 | < 0.001 |
| 8 h | 574 | 0.4 | 5.6 | 34.8 | 51.9 | 7.3 | |
| ≥ 9 h | 49 | 2.0 | 4.1 | 8.2 | 38.8 | 46.9 | |
| Hours of Sleep at Enrolment to the Whitehall II Cohort |
|||||||
| ≤ 5 h | 6 h | 7 h | 8 h | ≥ 9 h | |||
| Included in the study analyses, N (%) | 3960 | 135 (3.4) | 1092 (27.6) | 2127 (53.7) | 578 (14.6) | 28 (0.7) | |
| Excluded from the study analyses, N (%) | 2903 | 137 (4.7) | 824 (28.3) | 1457 (50.2) | 459 (15.8) | 26 (0.9) | |
+
Figures are unadjusted means (standard errors) for age and percentages for education, occupational position and sleep duration;
*
P-value for heterogeneity.