Table 7 Sensitivity analysis: use of inverse-probability weighting (IPW) to account for missing data.
From: Association of sleep duration in middle and old age with incidence of dementia
N cases/N total | Main analysis | Analysis using IPW to account for missing data | |||
|---|---|---|---|---|---|
HRa (95% CI) | P valueb | HRa (95% CI) | P valueb | ||
Sleep duration at age 50 | |||||
Short: ≤6 h | 211/3149 | 1.22 (1.01–1.48) | 0.04 | 1.21 (0.99–1.48) | 0.06 |
Normal: 7 h | 219/3624 | 1 (ref.) | 1 (ref.) | ||
Long: ≥8 h | 91/1186 | 1.25 (0.98–1.60) | 0.07 | 1.28 (0.99–1.66) | 0.06 |
Sleep duration at age 60 | |||||
Short: ≤6 h | 192/2759 | 1.37 (1.10–1.72) | 0.005 | 1.31 (1.03–1.66) | 0.03 |
Normal: 7 h | 142/2988 | 1 (ref.) | 1 (ref.) | ||
Long: ≥8 h | 75/1417 | 1.15 (0.87–1.52) | 0.34 | 1.25 (0.93–1.66) | 0.14 |
Sleep duration at age 70 | |||||
Short: ≤6 h | 171/2429 | 1.24 (0.98–1.57) | 0.10 | 1.14 (0.88–1.46) | 0.32 |
Normal: 7 h | 131/2578 | 1 (ref.) | 1 (ref.) | ||
Long: ≥8 h | 90/1509 | 1.15 (0.88–1.51) | 0.60 | 1.14 (0.85–1.52) | 0.39 |
Trajectories of sleep duration between age 50 and 70 | |||||
Persistent short | 103/1358 | 1.30 (1.00–1.69) | 0.048 | 1.24 (0.94–1.64) | 0.13 |
Persistent normal | 141/2520 | 1 (ref.) | 1 (ref.) | ||
Persistent long | 35/461 | 1.28 (0.88–1.85) | 0.20 | 1.33 (0.90–1.96) | 0.15 |
Change from short to normal | 61/1086 | 1.20 (0.89–1.63) | 0.23 | 1.21 (0.88–1.69) | 0.24 |
Change from normal to long | 47/946 | 1.02 (0.73–1.42) | 0.90 | 1.02 (0.71–1.45) | 0.93 |
Change from normal to short | 39/504 | 1.13 (0.79–1.62) | 0.50 | 1.12 (0.75–1.68) | 0.57 |
Accelerometer-assessed sleep duration | |||||
Tertile 1: 1 h 16 min–6 h 13 min | 53/1296 | 1.63 (1.04–2.57) | 0.03 | 1.63 (1.03–2.59) | 0.04 |
Tertile 2: 6 h 14 min–7 h 0 min | 31/1296 | 1 (ref.) | 1 (ref.) | ||
Tertile 3: 7 h 1 min–10 h 6 min | 27/1296 | 0.78 (0.46–1.32) | 0.36 | 0.82 (0.47–1.41) | 0.82 |
