Table 4.
Sleep quality and smoking characteristics of study population grouped by sleep duration.
| Sleep duration on weekdays | ||||
|---|---|---|---|---|
| ≤6 h | 6–9 h | ≥9 h | p-values | |
| (n = 1,118) | (n = 5,652) | (n = 1,499) | ||
| Sleep quality | ||||
| Sleep duration (h) | 5.23 (0.969) | 7.54 (0.617) | 9.74 (1.01) | *** |
| How often do you snore | *** | |||
| Never | 284 (27.9%) | 925 (28.2%) | 479 (34.2%) | |
| Rarely−1–2 nights a week | 226 (22.2%) | 828 (25.2%) | 316 (22.5%) | |
| Occasionally−3–4 nights a week | 185 (18.2%) | 648 (19.7%) | 235 (16.8%) | |
| Frequently−5 or more nights a week | 324 (31.8%) | 881 (26.8%) | 372 (26.5%) | |
| How often do you snore or have breath cessation | *** | |||
| Never | 778 (74.0%) | 2,592 (77.6%) | 1,104 (77.7%) | |
| Rarely−1–2 nights a week | 133 (12.7%) | 408 (12.2%) | 158 (11.1%) | |
| Occasionally−3–4 nights a week | 59 (5.61%) | 200 (5.98%) | 102 (7.18%) | |
| Frequently−5 or more nights a week | 81 (7.71%) | 142 (4.25%) | 57 (4.01%) | |
| Having trouble sleeping | 346 (30.9%) | 858 (24.2%) | 417 (27.9%) | *** |
| Smoking status | ||||
| Smoked at least 100 cigarettes in life (yes/no) | 489 (45.3%) | 1,293 (38.4%) | 577 (40.8%) | *** |
| Age started smoking cigarettes regularly (years) | 17.8 (6.06) | 18.0 (6.53) | 17.9 (6.33) | 0.89 |
| Do you now smoke cigarettes | ** | |||
| Every day | 202 (41.3%) | 417 (32.3%) | 186 (32.2%) | |
| Some days | 50 (10.2%) | 120 (9.28%) | 46 (7.97%) | |
| Not at all | 237 (48.5%) | 756 (58.5%) | 345 (59.8%) | |
| How soon after waking do you smoke | * | |||
| ≤ 5 min | 54 (27.7%) | 85 (20.3%) | 56 (31.3%) | |
| 6 ~ 30 min | 66 (33.8%) | 157 (37.5%) | 48 (26.8%) | |
| ≥30 min | 75 (38.5%) | 177 (42.2%) | 75 (41.9%) | |
| # days smoked cigarettes during past 30 days | 25.6 (8.65) | 24.2 (10.0) | 24.8 (9.19) | 0.16 |
| Average # cigarettes/day during past 30 days | 11.2 (8.06) | 11.2 (8.77) | 10.3 (7.53) | 0.42 |
| Tried to quit smoking (yes/no) | 126 (49.6%) | 290 (53.0%) | 125 (53.4%) | 0.62 |
*
p < 0.05,
**
p < 0.01,
***
p < 0.001 using statistical methods of ANOVA and Chi-squared test.