Table 2.
Descriptive summary of population characteristics stratified by average bedtime on weekdays and weekends.
| Independent variable | Bedtime average weekdays and weekends | Total | Value of p* | ||
|---|---|---|---|---|---|
| < 12:00 AM | 12:00–1:00 AM | > 1:00 AM | |||
| n = 129 | n = 98 | n = 125 | n = 352 | ||
| Sex, n (%) | |||||
| Males | 61 (47.29%) | 45 (45.92%) | 66 (52.80%) | 172 (48.86%) | 0.537 |
| Females | 68 (52.71%) | 53 (54.08%) | 59 (47.20%) | 180 (51.14%) | |
| BMI, n (%) | |||||
| Underweight | 5 (3.91%) | 1 (1.02%) | 1 (0.81%) | 7 (2.00%) | 0.051** |
| Normal Weight | 61 (47.66%) | 38 (38.78%) | 51 (41.13%) | 150 (42.86%) | |
| Overweight | 28 (21.88%) | 25 (25.51%) | 19 (15.32%) | 72 (20.57%) | |
| Obese | 34 (26.56%) | 34 (34.69%) | 53 (42.74%) | 121 (34.57%) | |
| Obesity, n (%) | |||||
| Non-Obese | 95 (73.64%) | 64 (65.31%) | 72 (57.60%) | 231 (65.62%) | 0.027 |
| Obese | 34 (26.36%) | 34 (34.69%) | 53 (42.40%) | 121 (34.38%) | |
| Screen time | |||||
| ≤ 2 Hours/Day | 21 (16.28%) | 7 (7.14%) | 9 (7.20%) | 37 (10.51%) | 0.027 |
| > 2 Hours/Day | 108 (83.72%) | 91 (92.86%) | 116 (92.80%) | 315 (89.49%) | |
| Medical history, n (%) | |||||
| No health problem | 104 (81.25%) | 73 (74.49%) | 92 (74.19%) | 269 (76.86%) | 0.718** |
| Diabetes | 2 (1.56%) | 3 (3.06%) | 2 (1.61%) | 7 (2.00%) | |
| Cardiovascular problems | 0 (0%) | 1 (1.02%) | 1 (0.81%) | 2 (0.57%) | |
| Others *** | 22 (17.19%) | 21 (21.43%) | 29 (23.39%) | 72 (20.57%) | |
| Taking Naps, n (%) | |||||
| No | 61 (47.29%) | 20 (20.41%) | 26 (20.80%) | 107 (30.40%) | <0.001 |
| Yes | 68 (52.71%) | 78 (79.59%) | 99 (79.20%) | 245 (69.60%) | |
| Snoring, n (%) | |||||
| No | 86 (66.67%) | 61 (62.24%) | 81 (64.80%) | 228 (64.77%) | 0.788 |
| Yes | 43 (33.33%) | 37 (37.76%) | 44 (35.20%) | 124 (35.23%) | |
| Interrupted sleep, n (%) | |||||
| No | 50 (38.76%) | 48 (48.98%) | 48 (38.40%) | 146 (41.48%) | 0.207 |
| Yes | 79 (61.24%) | 50 (51.02%) | 77 (61.60%) | 206 (58.52%) | |
| Difficulty waking-up in the morning, n (%) | |||||
| No | 31 (24.03%) | 19 (19.39%) | 19 (15.20%) | 69 (19.60%) | 0.207 |
| Yes | 98 (75.97%) | 79 (80.61%) | 106 (84.80%) | 283 (80.40%) | |
| Difficulty falling asleep, n (%) | |||||
| No | 99 (77.34%) | 65 (66.33%) | 88 (70.97%) | 252 (72.00%) | 0.179 |
| Yes | 29 (22.66%) | 33 (33.67%) | 36 (29.03%) | 98 (28.00%) | |
| Feeling sleepy during the day, n (%) | |||||
| No | 20 (15.50%) | 2 (2.04%) | 7 (5.60%) | 29 (8.24%) | 0.001** |
| Yes | 109 (84.50%) | 96 (97.96%) | 118 (94.40%) | 323 (91.76%) | |
| Waking-up during night sleep, n (%) | |||||
| No | 70 (55.12%) | 55 (56.12%) | 67 (54.03%) | 192 (55.01%) | 0.952 |
| Yes | 57 (44.88%) | 43 (43.88%) | 57 (45.97%) | 157 (44.99%) | |
| Sleep debt > 1 h, n (%) | |||||
| ≤ 1 h or absent sleep debt | 29 (22.48%) | 5 (5.10%) | 3 (2.40%) | 37 (10.51%) | <0.001** |
| > 1 h | 100 (77.52%) | 93 (94.90%) | 122 (97.60%) | 315 (89.49%) | |
| Severe sleep debt > 2 h, n (%) | |||||
| ≤ 2 h or absent severe sleep debt | 52 (40.31%) | 12 (12.24%) | 6 (4.80%) | 70 (19.89%) | <0.001 |
| > 2 severe sleep debt | 77 (59.69%) | 86 (87.76%) | 119 (95.20%) | 282 (80.11%) | |
| Social jetlag, n (%) | |||||
| < 1.5 h or absent SJL | 43 (33.33%) | 48 (48.98%) | 85 (68.00%) | 176 (50.00%) | <0.001 |
| ≥ 1.5 h | 86 (66.67%) | 50 (51.02%) | 40 (32.00%) | 176 (50.00%) | |
*
= p-value < 0.05 calculated by chi-square test except when one or more of the cells counts is less than 5.
**
= p-value < 0.05 calculated by Fisher’s exact test.
***
=Others medical conditions includes: anxiety, n = 15(4.2%); depression, n = 7(2%); asthma, n = 21(6%); irritable bowel syndrome, n = 5(1.4%); migraine, n = 5(1.4%); anemia, n = 3(0.8%); sickle cell anemia, n = 3(0.8%); kidney stone, n = 2(0.5%); stomach problem, n = 3(0.8%); seizure n = 1(0.3%); bone marrow transplant, n = 1(0.3%); whooping cough, n = 1(0.3%); Glucose-6-phosphate dehydrogenase (G6PD), n = 1(0.3%); polycystic ovary syndrome n = 1(0.3%); bleeding nose, n = 1(0.3%).