Table 3.

Cancer, leukaemia, ALL, and non-leukaemia cancer hazard ratios in the pooled dataset using a time-varying coefficient for birthweight across two time periods (age at diagnosis <3 vs. ≥3 years old) adjusting for sex and gestational age

		Diagnosed <3 years old			Diagnosed ≥3 years old			Comparison of HRs between time periods, P-value
Diagnosis	Birthweight	Cases	HR	95% CI	Cases	HR	95% CI
Cancer	≥4.0 kg	182	0.84	0.56, 1.27	195	1.60	1.13, 2.26	0.018
	Top 10%		0.80	0.46, 1.39		1.64	1.10, 2.44	0.037
	Continuous		1.08	0.82, 1.42		1.44	1.11, 1.88	0.099
Leukaemia	≥4.0 kg	59	1.08	0.55, 2.13	56	1.56	0.84, 2.88	0.43
	Top 10%		1.08	0.46, 2.54		1.55	0.72, 3.30	0.54
	Continuous		1.29	0.79, 2.11		1.57	0.96, 2.57	0.56
ALL	≥4.0 kg	49	1.02	0.48, 2.15	49	1.49	0.77, 2.88	0.45
	Top 10%		1.07	0.42, 2.73		1.28	0.54, 3.03	0.79
	Continuous		1.23	0.72, 2.11		1.34	0.78, 2.30	0.81
Non-leukaemia	≥4.0 kg	123	0.75	0.45, 1.24	139	1.62	1.06, 2.46	0.020
	Top 10%		0.67	0.33, 1.38		1.68	1.05, 2.68	0.035
	Continuous		0.99	0.71, 1.38		1.39	1.02, 1.91	0.10

Model 2: Stratified Cox proportional hazard regression with a time-varying coefficient for birthweight based on an indicator function for time defined at the age of diagnosis cut-point adjusted for gestational age and sex of the child.