Associations between age, sex, BMI and smoking history and sleep-related symptoms
| Age | Sex | BMI | Smoking history | |
| Insomnia symptoms | ||||
| Difficulties initiating sleep | 1.02 (1.01–1.03) | 2.16 (1.77–2.64) | 1.02 (1.01–1.05) | 0.81 (0.66–0.99) |
| Difficulties maintaining sleep | 1.04 (1.03–1.05) | 1.80 (1.56–2.07) | 1.01 (1.00–1.03) | 1.09 (0.95–1.26) |
| Early morning awakenings | 1.02 (1.01–1.03) | 1.52 (1.28–1.80) | 1.01 (1.00–1.03) | 1.02 (0.85–1.21) |
| Any insomnia symptom | 1.03 (1.02–1.04) | 1.75 (1.53–1.99) | 1.02 (1.01–1.03) | 1.07 (0.93–1.22) |
| Number of insomnia symptoms | ||||
| 1 | 1.03 (1.01–1.04) | 1.47 (1.26–1.71) | 1.02 (1.00–1.03) | 1.15 (0.98–1.34) |
| 2 | 1.04 (1.02–1.06) | 2.11 (1.69–2.64) | 1.02 (1.00–1.05) | 1.01 (0.80–1.26) |
| 3 | 1.04 (1.02–1.06) | 2.62 (1.93–3.53) | 1.03 (0.99–1.06) | 0.89 (0.66–1.20) |
| Daytime sleepiness | ||||
| Epworth Sleepiness Scale score >10 | 0.99 (0.98–1.00) | 0.95 (0.81–1.12) | 1.01 (0.99–1.03) | 1.28 (1.08–1.52) |
| Sleep duration | ||||
| Short sleepers (≤6 hours) | 1.01 (0.99–1.02) | 0.88 (0.77–1.00) | 1.03 (1.02–1.05) | 0.83 (0.72–0.96) |
| Normal sleepers (6–9 hours) | 0.99 (0.98–0.99) | 1.08 (0.95–1.23) | 0.96 (0.95–0.98) | 1.20 (1.05–1.38) |
| Long sleepers (≥9 hours) | 1.03 (1.01–1.06) | 1.35 (0.96–1.89) | 1.02 (0.99–1.06) | 0.95 (0.67–1.34) |
*Bold text indicates statistical significance.
BMI, body mass index.