Table 1.

Incidence rate ratios for self-harm from age 15 according to child-parent separation status at birth, at 15th birthday, and by number of changes in separation status through upbringing.

Child-parent separation status	Exposure prevalence (%)	npersons (self-harm)	Incidence ratea	IRRb	(95% CI)	Adj. IRRc	(95% CI)
Separation status at birth:
Not separated	93.4	26,601	17.5	1.00	(Ref.)	1.00	(Ref.)
Separated from father	6.2	3747	36.1	2.12	(2.05–2.20)	1.53	(1.48–1.58)
Separated from mother	0.17	66	16.7	1.28	(1.00–1.62)	1.16	(0.90–1.46)
Separated from both parents	0.21	70	12.0	1.07	(0.84–1.35)	0.94	(0.73–1.17)
Separation status at 15th birthday:
Not separated	71.2	15,734	13.1	1.00	(Ref.)	1.00	(Ref.)
Separated from father	22.8	10,660	31.3	2.23	(2.17–2.28)	1.83	(1.79–1.88)
Separated from mother	4.2	2084	32.8	2.44	(2.33–2.55)	2.02	(1.93–2.12)
Separated from both parents	1.7	2006	66.2	5.50	(5.25–5.77)	3.30	(3.14–3.46)
No. of separation status changes:
0	67.7	14,644	12.9	1.00	(Ref.)	1.00	(Ref.)
1	21.1	8696	26.7	1.99	(1.94–2.04)	1.72	(1.68–1.77)
2	6.3	3459	36.1	2.68	(2.58–2.78)	2.17	(2.09–2.25)
3	3.1	2039	42.8	3.16	(3.01–3.31)	2.30	(2.19–2.41)
4	1.0	856	54.4	4.02	(3.75–4.30)	2.67	(2.49–2.86)
5 or more	0.7	790	71.9	5.24	(4.88–5.63)	3.17	(2.94–3.41)

^aIncidence rate per 10,000 person-years at risk.

^bIRR - Incidence rate ratio.

^cAdj. IRR - Adjusted incidence rate ratio; adjusted for parental socioeconomic status at cohort members’ 15th birthdays.