Cox proportional HR with 95% CI for the association between hospitalisation before and after the first childbirth, and new sickness absence (SA) in year 3–5 after T0, in twins who had their first childbirth during 1994–2009 (n=2792)
| Hospitalisation status before and after childbirth | SA in year 3–5 after T0 (regardless of the number of days) | Long-term SA (>90 days) in year 3–5 after T0 | ||||||
|---|---|---|---|---|---|---|---|---|
| Model a* | Model b† | Model c‡ | Discordant twin pairs§, † | Model a* | Model b† | Model c‡ | Discordant twin pairs¶,† | |
| No hospitalisation either before T0** or during year 1–2 after T0†† | 1 (REF) | 1 (REF) | 1 (REF) | 1 (REF) | 1 (REF) | 1 (REF) | 1 (REF) | 1 (REF) |
| Hospitalisation before T0** but not during year 1–2 after T0†† | 1.2 (1.0 to 1.5) | 1.2 (1.0 to 1.4) | 1.2 (1.0 to 1.4) | 1.0 (0.8 to 1.3) | 2.3 (1.6 to 3.4) | 2.1 (1.5 to 3.1) | 2.2 (1.5 to 3.1) | 1.2 (0.8 to 1.7) |
| No hospitalisation before T0** but during year 1–2 after T0†† | 1.2 (1.1 to 1.4) | 1.2 (1.0 to 1.4) | 1.1 (0.9 to 1.2) | 1.1 (0.9 to 1.4) | 2.0 (1.5 to 2.8) | 1.9 (1.4 to 2.7) | 1.9 (1.4 to 2.7) | 1.4 (1.0 to 2.1) |
| Hospitalisation before T0** and during year 1–2 after T0†† | 2.0 (1.6 to 2.5) | 1.8 (1.4 to 2.2) | 1.6 (1.3 to 2.1) | 1.6 (1.1 to 2.2) | 4.2 (2.7 to 6.4) | 3.5 (2.3 to 5.3) | 3.5 (2.3 to 5.4) | 1.5 (0.9 to 2.4) |
Three models for adjustments as well as for discordant twin pairs.
*Adjusted for birth year.
†Model a, and additional adjustments for delivery year and educational level.
‡Model b, and additional adjustments for subsequent deliveries.
§Twin pairs where one had an SA during the follow-up and the other did not (n=542).
¶Twin pairs where one had a long-term SA during the follow-up and the other did not (n=184).
**During the period 1–5 years prior to T0.
††Diagnoses O00-O99 excluded.