Mediation analysis of gestational age, congenital heart defects, and infant birth-weight

BMC Research Notes

Table 2 Results from the three regression models: having birth weight as the dependent variable (Model 1 and Model 3) and having gestational age as the dependent variable (Model 2)

Variable	Parameter estimate	Standard error	t–value	p–value
(a) Model 1 (dependent variable is birth weight in grams)
Intercept	3349.39	14.82	226.07	<0.0001
CHD¹	−279.00	15.82	−17.64	<0.0001
Child’s sex²	137.53	15.81	8.70	<0.0001
1–10 cigarettes/day³	−191.44	22.14	−8.64	<0.0001
11–20 cigarettes/day³	−167.19	22.96	−7.28	<0.0001
21–39 cigarettes/day³	−224.75	40.60	−5.54	<0.0001
40 or more cigarettes/day³	−240.76	68.92	−3.49	0.0005
(b) Model 2 (dependent variable is gestational age in weeks)
Intercept	39.64	0.06	708.67	<0.0001
CHD¹	−0.69	0.06	−11.54	<0.0001
Child’s sex²	0.04	0.06	0.64	0.5198
1–10 cigarettes/day³	−0.26	0.08	−3.16	0.0016
11–20 cigarettes/day³	−0.21	0.09	−2.46	0.0138
21–39 cigarettes/day³	−0.21	0.15	−1.38	0.1662
40 or more cigarettes/day³	−0.07	0.26	−0.27	0.7880
(c) Model 3 (dependent variable is birth weight in grams)
Intercept	−3157.30	99.75	−31.65	<0.0001
Gestational age	164.13	2.50	65.68	<0.0001
CHD¹	−165.92	12.53	−13.24	<0.0001
Child’s sex²	131.23	12.41	10.57	<0.0001
1–10 cigarettes/day³	−148.04	17.39	−8.51	<0.0001
11–20 cigarettes/day³	−132.14	18.03	−7.33	<0.0001
21–39 cigarettes/day³	−189.91	31.87	−5.96	<0.0001
40 or more cigarettes/day³	−229.28	54.09	−4.24	<0.0001

ISSN: 1756-0500