Analysis of subgroups for the association between sleep duration and all-cause mortality according to the models of multivariate analysis carried out for control of confounding factors in the individual studies
| Number of cohorts | Relative risk (95% CI) | I2 statistic (%) | Q test p Value | |
|---|---|---|---|---|
| Short sleep | ||||
| Unadjusted | 15 | 1.07 (0.96 to 1.20) | 78.2 | <0.001 |
| Model 1† | 9 | 1.17 (1.00 to 1.36) | 43.2 | 0.080 |
| Model 2‡ | 4 | 1.20 (0.92 to 1.58) | 66.4 | 0.030 |
| Model 3§ | 7 | 1.10 (0.99 to 1.23) | 0.0 | 0.587 |
| Model 4¶ | 18 | 1.06 (1.00 to 1.13) | 22.6 | 0.186 |
| Long sleep | ||||
| Unadjusted | 16 | 1.58 (1.33 to 1.88)* | 94.7 | <0.001 |
| Model 1† | 11 | 1.67 (1.36 to 2.05)* | 76.2 | <0.001 |
| Model 2‡ | 5 | 1.80 (1.47 to 2.12)* | 52.6 | 0.077 |
| Model 3§ | 9 | 1.68 (1.47 to 1.93)* | 21.3 | 0.261 |
| Model 4¶ | 18 | 1.35 (1.25 to 1.45)* | 49.1 | 0.010 |
*p<0.05.
†Model 1: Adjusted for age and sex.
‡Model 2: Adjusted for variables in Model 1 plus demographic and lifestyle characteristics.
§Model 3: Adjusted for variables in Model 2 plus comorbidities.
¶Model 4: Adjusted for variables in Model 3 plus additional variables (medication use, daytime sleepiness, nighttime awakening, afternoon nap duration, habitual snoring, cognitive function, quality of life, instrumental activity of daily living limitations, health status and frailty).