Table 2.

Maternal adjusted trajectories of offspring depressive symptoms (n = 5029)

Parameter	Beta	95% CIs		s.e.	P-value	Baseline + risk group score parameter	95% CI + risk group score parameter
No ANTD/no PNTD Intercept	5.353	5.144	5.562	0.107	<0.001	–	–	–
No ANTD/no PNTD agea	0.328	0.290	0.366	0.020	<0.001	–	–	–
No ANTD/no PNTD age^2b	−0.088	−0.099	−0.076	0.006	<0.001	–	–	–
No ANTD/no PNTD age^3c	−0.005	−0.006	−0.004	0.001	<0.001	–	–	–
No ANTD/no PNTD age^4d	0.002	0.001	0.002	0.0001	<0.001	–	–	–
Yes ANTD/no PNTD intercept	1.430	0.868	1.992	0.287	<0.001	6.783	6.219	7.347
Yes ANTD/no PNTD agea	0.092	−0.052	0.235	0.073	0.21	0.420	0.282	0.558
Yes ANTD/no PNTD age^2b	−0.046	−0.091	−0.001	0.023	0.046	−0.133	−0.177	−0.090
Yes ANTTD/no PNTD age^3c	−0.001	−0.005	0.003	0.002	0.593	−0.006	−0.009	0.002
Yes ANTD/no PNTD age^4d	0.001	−0.00001	0.002	0.0005	0.054	0.002	0.00200	0.003
No ANTD/yes PNTD intercept	0.776	0.114	1.439	0.338	0.022	6.130	5.466	6.793
No ANTD/yes PNTD agea	0.179	0.010	0.348	0.086	0.038	0.507	0.342	0.672
No ANTD/yes PNTD age^2b	0.002	−0.051	0.054	0.027	0.953	−0.086	−0.137	−0.035
No ANTD/yes PNTD age^3c	−0.002	−0.006	0.003	0.002	0.412	−0.007	−0.011	−0.002
No ANTD/yes PNTD age^4d	0.0000	−0.001	0.001	0.001	0.989	0.002	0.001	0.003
Yes ANTD/yes PNTD intercept	1.719	0.844	2.594	0.447	<0.001	7.072	6.191	7.953
Yes ANTD/yes PNTD agea	0.370	0.140	0.601	0.117	0.002	0.698	0.471	0.925
Yes ANTD/yes PNTD age^2b	−0.035	−0.108	0.038	0.037	0.348	−0.122	−0.194	−0.051
Yes ANTD/yes PNTD age^3c	−0.008	−0.014	−0.002	0.003	0.01	−0.013	−0.018	−0.007
Yes ANTD/yes PNTD age^4d	0.001	−0.0003	0.003	0.001	0.124	0.003	0.0010	0.004

The No ANTD/no PNTD variable is the baseline (reference) group. There are four groups. Each group has an intercept and four terms resulting in four trajectories per group. The different terms (a–d) for each group are further parameters to account for the non-linearity of the trajectories as seen by the fact that the slope is steeper at different ages. For further information on the nature of change in rate of depressive symptoms as per the four terms at different ages, please see the Supplementary material. The intercept for each group was determined by manually adding the baseline intercept for No ANTD/no PNTD to the intercept of the group being compared. Similarly, the rate of change for each subsequent group was determined by adding the rate of change for the baseline group to the rate of change of the group being compared. This is highlighted in the column entitled ‘Baseline + risk group score parameter’. For ease of interpretation, we present the original regression coefficients and their 95% CI, s.e. and P-values first. The s.e. and P-value represent the difference between the baseline trajectory and the additional parameter. Then we present the scores for each group when the baseline group is added to the ‘higher’ risk group. This analysis was adjusted for sex, paternal depression, maternal education at birth, parity and maternal smoking in pregnancy. Intercepts are centred to age 16, the mean age of all assessments.

ANTD, antenatal depression; PNTD, postnatal depression.

^a.linear slope.

^b.quadratic slope.

^c.cubic change in speed of slope.

^d.quartic slope.