Table 7.
Sensitivity analysis: use of inverse-probability weighting (IPW) to account for missing data.
| 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 |
CI confidence intervals, HR hazard ratio, IPW inverse-probability weighting, h hour, min minute.
aHR estimated from a Cox regression adjusted for age (timescale), sex, ethnicity, education, and marital status, alcohol consumption, physical activity, smoking status, and fruit and vegetable consumption, BMI, hypertension, diabetes, cardiovascular disease, GHQ depression, and CNS medications.
bTwo-sided for HR in comparison with the reference (ref.) category, without adjustment for multiple comparisons.