Table 1. Demographic characteristics of the GWAS cohort.
| Morning persons N (% of total) | Evening persons N (% of total) | Proportion that are morning persons (%) | |
|---|---|---|---|
| Total | 38,937 (100.0) | 50,346 (100.0) | 43.6 |
| Sex | |||
| Male | 19,569 (50.3) | 29,713 (59.0) | 39.7 |
| Female | 19,368 (49.7) | 20,633 (41.0) | 48.4 |
| Age | |||
| <30 | 3,684 (9.5) | 11,521 (22.9) | 24.2 |
| 30–45 | 8,809 (22.6) | 19,470 (38.7) | 31.2 |
| 45–60 | 12,295 (31.6) | 11,111 (22.1) | 52.5 |
| >60 | 14,149 (36.3) | 8,244 (16.4) | 63.1 |
| Insomnia | |||
| No | 13,809 (79.1) | 14,180 (60.3) | 49.3 |
| Yes | 3,639 (20.9) | 9,348 (39.7) | 28.0 |
| Sleep apnoea | |||
| No | 22,827 (89.5) | 30,822 (88.9) | 42.5 |
| Yes | 2,673 (10.5) | 3,862 (11.1) | 40.9 |
| Sleep needed | |||
| <8 h | 7,549 (56.6) | 8,715 (46.4) | 46.4 |
| ≥8 h | 5,782 (43.4) | 10,068 (53.6) | 36.4 |
| Sound sleeper | |||
| No | 8,772 (49.3) | 10,062 (42.0) | 46.6 |
| Yes | 9,020 (50.7) | 13,901 (58.0) | 39.4 |
| Restless leg syndrome | |||
| No | 11,877 (92.0) | 16,476 (91.3) | 41.9 |
| Yes | 1,035 (8.0) | 1,566 (8.7) | 39.8 |
| Sweat while sleeping | |||
| No | 12,809 (72.9) | 16,273 (68.3) | 44.0 |
| Yes | 4,765 (27.1) | 7,546 (31.7) | 38.7 |
| Sleep walk | |||
| No | 12,145 (92.9) | 16,773 (90.9) | 42.0 |
| Yes | 934 (7.1) | 1,681 (9.1) | 35.7 |
| Average daily sleep duration | |||
| <8 h | 8,146 (67.6) | 11,102 (68.5) | 42.3 |
| ≥8 h | 3,902 (32.4) | 5,095 (31.5) | 43.4 |
| Depression | |||
| No | 20,217 (77.6) | 24,162 (68.8) | 45.6 |
| Yes | 5,835 (22.4) | 10,977 (31.2) | 34.7 |
| BMI (kg m−2) | |||
| ≤18.5 (Underweight) | 609 (1.8) | 947 (2.1) | 39.1 |
| 18.5–25 (Normal) | 14,561 (42.9) | 19,261 (41.8) | 43.1 |
| 25–30 (Overweight) | 12,803 (35.6) | 15,440 (33.5) | 45.3 |
| >30 (Obese) | 6,677 (19.7) | 10,464 (22.7) | 39.0 |
BMI, body mass index.