Table 2.
Associations between various factors and nocturnal sleep duration. Results are expressed as effect size in minutes (99% CI)
| Variable | Univariate analysis |
Model 1* (r2 = 0.39) |
Model 2** (r2 = 0.47) |
|||
|---|---|---|---|---|---|---|
| β (99%CI) | P† | β (99%CI) | P† | β (99%CI) | P† | |
| Male sex | −0.9 (−4.1; 2.4) | 0.493 | ||||
| Age | −6.0 (−6.9; −5.1) | < 0.001 | −5.5 (−6.2; −4.8) | < 0.001 | −6.0 (−7.7; −4.2) | < 0.001 |
| Education level | < 0.001 | 0.453 | 0.247 | |||
| High | ref. | ref. | ref. | |||
| Medium | −14.9 (−18.7; 11.0) | 0.7 (−2.6; 4.0) | −4.6 (−11.0; 1.7) | |||
| Low | −7.5 (−12.8; 2.2) | −2.8 (−7.4; 1.7) | −3.3 (−13.2; 6.5) | |||
| Country | < 0.001 | < 0.001 | < 0.001 | |||
| Estonia | −74.9 (−79.7; −70.1) | −72.5 (−78.0; −67.9) | −59.5 (−70.4; −48.6) | |||
| Italy | −66.5 (−71.1; −62.0) | −64.5 (−69.6; −60.0) | −49.7 (−60.5; −38.9) | |||
| Hungary | −44.8 (−50.1; −39.6) | −39.9 (−45.4; −34.8) | −30.6 (−42.5; −18.8) | |||
| Cyprus | −35.6 (−40.8; −30.4) | −35.5 (−41.4; −30.5) | −21.3 (−39.9; −2.8) | |||
| Spain | −31.7 (−38.1; −25.4) | −29.8 (−36.4; −22.9) | −23.7 (−37.0; −10.3) | |||
| Sweden | ref. | ref. | ref. | |||
| Germany | 14.8 (10.3; 19.4) | 17.5 (12.5; 22.2) | 28.6 (18.2; 38.9) | |||
| Belgium | 24.9 (18.0; 31.7) | 24.6 (17.6; 31.3) | 30.0 (15.6; 44.5) | |||
| Fall/winter vs. spring/summer | 10.5 (7.1; 13.9) | < 0.001 | 4.0 (−1.0; 9.0) | < 0.041 | 3.8 (−6.3; 13.8) | 0.331 |
| Daylight hours | −3.1 (−3.7; −2.5) | < 0.001 | −0.4 (−1.3; 0.5) | < 0.232 | −0.3 (−2.0; 1.4) | 0.655 |
| Normal weight vs. overweight | 20.6 (17.6; 23.7) | < 0.001 | 5.4 (−1.1; 11.7) | 0.034 | ||
| Screen time | < 0.001 | 0.043 | ||||
| Not at all | ref. | ref. | ||||
| < 30 min | 0.5 (−8.3; 9.4) | −3.5 (−22.3; 15.3) | ||||
| < 1 h | −6.5 (−14.9; 1.9) | −9.8 (−27.8; 8.1) | ||||
| > 1 h and < 2 h | −14.3 (−22.6; −5.9) | −10.8 (−28.7; 7.1) | ||||
| > 2 h and < 3 h | −21.7 (−30.2; −13.1) | −14.6 (−32.8; 3.6) | ||||
| > 3 h | −34.6 (−43.1; −26.1) | −13.2 (−31.5; 5.0) | ||||
| Play outdoors | 4.4 (3.6; 5.5) | < 0.001 | 0.9 (−1.3; 3.1) | 0.301 | ||
| Time spent in sports club | < 0.001 | |||||
| < 1 h | 21.1 (6.0; 36.3) | |||||
| ≥ 1 h and < 4 h | 23.0 (16.8; 29.3) | |||||
| ≥ 4 h | ref. | |||||
| Mean (min) of moderate to vigorous activity | −0.1 (−0.3; 0.1) | 0.134 | ||||
*
Including age, parental education level, country, season, daylight hours; n = 8093.
**
Model 1 + modifiable variables (overweight, screen time, and time playing outside); n = 8093.
†
P-values of multivariate analyses of variance.