Table 3.
Cox proportional hazards model for insomnia symptoms as a predictor of time-to-onset of physician-diagnosed memory problems – 2006–2016 Health and Retirement Study (n=9,518)
| Unadjusted | Model I a | Model II b | Model III c | |||||
|---|---|---|---|---|---|---|---|---|
| HR | 95% CI | HR | 95% CI | HR | 95% CI | HR | 95% CI | |
| Insomnia symptoms: | ||||||||
| Any: | ||||||||
| Yes | 1.08 | 0.95, 1.23 | 1.03 | 0.90, 1.17 | 1.04 | 0.91, 1.19 | 0.96 | 0.84, 1.12 |
| No | Ref. | -- | Ref. | -- | Ref. | -- | Ref. | -- |
| Continuous | 1.00 | 0.97, 1.03 | 0.98 | 0.95, 1.02 | 0.98 | 0.95, 1.02 | 0.95 | 0.92, 0.99 |
| Severe: | ||||||||
| Yes | 1.06 | 0.89, 1.26 | 1.12 | 0.95, 1.33 | 1.12 | 0.95, 1.33 | 1.21 | 1.02, 1.44 |
| No | Ref. | -- | Ref. | -- | Ref. | -- | Ref. | -- |
| Continuous | 1.04 | 0.98, 1.11 | 1.07 | 1.00, 1.13 | 1.06 | 1.00, 1.13 | 1.10 | 1.04, 1.18 |
| Change in insomnia symptoms (Any): | ||||||||
| 2006–2010: | ||||||||
| Increase | 1.13 | 0.93, 1.36 | 1.04 | 0.87, 1.26 | 1.04 | 0.86, 1.26 | 1.02 | 0.84, 1.23 |
| No change | Ref. | -- | Ref. | -- | Ref. | -- | Ref. | -- |
| Decrease | 1.32 | 1.08, 1.61 | 1.23 | 1.01, 1.50 | 1.22 | 0.99, 1.48 | 1.16 | 0.95, 1.42 |
| 2010–2014: | ||||||||
| Increase | 1.06 | 0.84, 1.36 | 1.00 | 0.79, 1.26 | 0.99 | 0.79, 1.26 | 0.98 | 0.77, 1.24 |
| No change | Ref. | -- | Ref. | -- | Ref. | -- | Ref. | -- |
| Decrease | 1.23 | 0.97, 1.56 | 1.12 | 0.89, 1.41 | 1.12 | 0.88, 1.41 | 1.05 | 0.83, 1.33 |
| 2006–2014: | ||||||||
| Increase | 1.06 | 0.84, 1.36 | 1.00 | 0.79, 1.27 | 0.99 | 0.79, 1.26 | 0.97 | 0.77, 1.24 |
| No change | Ref. | -- | Ref. | -- | Ref. | -- | Ref. | -- |
| Decrease | 1.23 | 0.97, 1.56 | 1.12 | 0.89, 1.41 | 1.12 | 0.88, 1.41 | 1.05 | 0.83, 1.33 |
| Change in insomnia symptoms (Severe): | ||||||||
| 2006–2010: | ||||||||
| Increase | 1.51 | 1.27, 1.79 | 1.39 | 1.17, 1.65 | 1.38 | 1.16, 1.64 | 1.41 | 1.18, 1.68 |
| No change | Ref. | -- | Ref. | -- | Ref. | -- | Ref. | -- |
| Decrease | 1.18 | 0.99, 1.39 | 1.12 | 0.95, 1.33 | 1.12 | 0.94, 1.32 | 1.14 | 0.96, 1.36 |
| 2010–2014: | ||||||||
| Increase | 1.42 | 1.16, 1.74 | 1.34 | 1.09, 1.64 | 1.34 | 1.09, 1.64 | 1.34 | 1.09, 1.64 |
| No change | Ref. | -- | Ref. | -- | Ref. | -- | Ref. | -- |
| Decrease | 1.19 | 0.96, 1.48 | 1.13 | 0.91, 1.39 | 1.14 | 0.92, 1.41 | 1.13 | 0.91, 1.39 |
| 2006–2014: | ||||||||
| Increase | 1.87 | 1.53, 2.29 | 1.73 | 1.41, 2.10 | 1.70 | 1.39, 2.08 | 1.72 | 1.40, 2.11 |
| No change | Ref. | -- | Ref. | -- | Ref. | -- | Ref. | -- |
| Decrease | 1.22 | 0.99, 1.50 | 1.22 | 0.99, 1.49 | 1.20 | 0.98, 1.48 | 1.24 | 0.99, 1.54 |
Abbreviations: HR=hazard ratio; CI: confidence interval.
a
Model I was adjusted for socio-demographic characteristics;
b
Model II was adjusted for socio-demographic and lifestyle characteristics;
c
Model III was adjusted for socio-demographic, lifestyle and health characteristics.