Table 3.

Mean differences in early predictors and adolescent outcomes by trajectory group for boys

Variables	Trajectory group								F-test
	Low		Increasing		Decreasing		High
	Mean	SD	Mean	SD	Mean	SD	Mean	SD
Early predictors
BME background	0.11a	0.31	0.10a	0.31	0.17b	0.37	0.16b	0.36	F(3, 387) = 5.30**
Teenage mother	0.03	0.16	0.03	0.18	0.07	0.25	0.04	0.20	F(3, 387) = 2.72
Low birth weight	0.06a	0.24	0.06a	0.24	0.07ab	0.26	0.12b	0.32	F(3, 387) = 5.30**
Single parent	0.14a	0.34	0.15a	0.36	0.18ab	0.38	0.25b	0.43	F(3, 387) = 11.65***
Parent low qualifications	0.18a	0.38	0.20ab	0.40	0.26b	0.44	0.26b	0.44	F(3, 387) = 6.62***
Income quintile	3.07a	1.40	2.94ab	1.45	2.69b	1.39	2.35c	1.32	F(3, 387) = 41.72***
Social housing	0.21a	0.41	0.28b	0.45	0.31bc	0.46	0.38c	0.48	F(3, 387) = 20.95***
Maternal smoking in pregnancy	0.21a	0.41	0.26ab	0.44	0.27ab	0.44	0.31b	0.46	F(3, 387) = 7.11***
Maternal depressive symptoms	0.06a	0.24	0.11b	0.31	0.15bc	0.36	0.17c	0.38	F(3, 387) = 24.36***
Paternal depressive symptoms	0.05	0.21	0.05	0.22	0.07	0.26	0.06	0.24	F(3, 387) = 1.30
Self-reported adolescent outcomes
How many times had an alcoholic drink	0.92	1.30	0.89	1.44	0.86	1.29	0.78	1.26	F(3, 387) = 1.12
How often do you smoke	0.25a	0.76	0.43b	1.03	0.45ab	1.12	0.55b	1.28	F(3, 387) = 6.99***
How often smoke cannabis	0.10	0.53	0.15	0.59	0.13	0.60	0.23	0.78	F(3, 387) = 1.93
Ever self-harmed	0.08a	0.27	0.16b	0.36	0.08ab	0.27	0.14b	0.35	F(3, 387) = 6.90***
High BMI	0.14a	0.35	0.25b	0.43	0.15ab	0.36	0.22b	0.41	F(3, 387) = 7.02***
Hours spent on social networks	3.06	1.98	2.96	2.12	2.95	1.97	2.70	3.29	F(3, 387) = 0.71
Engaged in sexual activity	0.03	0.17	0.04	0.21	0.03	0.18	0.04	0.20	F(3, 387) = 0.38
Mental wellbeing	5.68a	1.02	5.38b	1.05	5.53ab	1.02	5.39b	1.09	F(3, 387) = 14.72***
Depressive symptoms	1.31a	0.36	1.45b	0.43	1.30a	0.33	1.46b	0.44	F(3, 387) = 17.34***
Low educational motivation	2.96a	0.45	2.84b	0.51	2.91ab	0.43	2.83b	0.53	F(3, 387) = 10.28***
How often argue with mother	2.72a	1.02	2.98b	1.04	2.74ab	1.06	2.75ab	1.21	F(3, 387) = 5.73***
How often argue with father	2.42	1.01	2.60	1.09	2.36	1.02	2.41	1.31	F(3, 387) = 2.95
Parent-reported adolescent outcomes
Conduct problems	0.10a	0.30	0.33b	0.47	0.12a	0.33	0.39b	0.49	F(3, 387) = 54.72***
Peer problems	0.13a	0.33	0.47b	0.50	0.15a	0.36	0.51b	0.50	F(3, 387) = 87.61***
Hyperactivity	0.10a	0.30	0.34b	0.47	0.12a	0.32	0.36b	0.48	F(3, 387) = 50.69***

F-tests and post-hoc analysis were conducted using svy in STATA, which reports design degrees of freedom for a complex clustered and stratified survey design. Post-hoc analyses using Bonferroni’s method identified significant pairwise comparisons (p < 0.05) between groups, shown when group means do not share any similar superscripts. *p < 0.05, ** p < 0.01, ***p < 0.001