. 2017 Sep 27;14(10):1132. doi: 10.3390/ijerph14101132

Table 3.

Results from logistic and linear regression models on the association between hyperactivity behaviors of young children and combinations of prenatal environmental tobacco smoke (ETS) exposure in different trimesters of pregnancy.

Prenatal ETS Exposure			Total, N	Hyperactivity Behaviors
1st Trimester	2nd Trimester	3rd Trimester		Logistic Regression (Used as a Categorical Variable)			Linear Regression (Used as a Continuous Variable)
				Cases, N (%)	Model 1 ^†	Model 2 ^‡	Score, Mean ± SE	Model 1 ^†	Model 2 ^§
				Cases, N (%)	Crude OR (95% CI)	Adjusted OR (95% CI)	Score, Mean ± SE	Crude β (95% CI) ^¶	Adjusted β (95% CI) ^¶
No	No	No	14,533	387 (2.7)	1.00	1.00	0.613 ± 0.004	Ref	Ref
Yes	No	No	401	186 (4.0)	1.52 (0.91–2.53)	1.33 (0.80–2.23)	0.697 ± 0.021	0.029 (0.018–0.039) ^c	0.023 (0.012–0.034) ^c
No	Yes	No	130	9 (6.9)	2.72 (1.37–5.39) ^b	2.36 (1.19–4.71) ^a	0.741 ± 0.037	0.040 (0.021–0.059) ^c	0.033 (0.014–0.051) ^c
No	No	Yes	190	10 (5.3)	2.03 (1.07–3.87) ^a	1.81 (0.95–3.46)	0.774 ± 0.030	0.046 (0.030–0.061) ^c	0.040 (0.024–0.055) ^c
Yes	Yes	No	107	8 (7.5)	2.95 (1.43–6.11) ^b	2.43 (1.17–5.07) ^a	0.819 ± 0.040	0.059 (0.038–0.080) ^c	0.050 (0.029–0.070) ^c
Yes	No	Yes	36	4 (11.1)	4.57 (1.61–12.98) ^b	3.78 (1.31–10.88) ^a	0.853 ± 0.070	0.067 (0.031–0.102) ^c	0.057 (0.022–0.092) ^b
No	Yes	Yes	202	12 (5.9)	2.31 (1.28–4.17) ^a	1.99 (1.10–3.61) ^a	0.679 ± 0.029	0.025 (0.010–0.040) ^b	0.017 (0.002–0.032) ^a
Yes	Yes	Yes	1849	105 (5.7)	2.20 (1.76–2.75) ^c	1.93 (1.53–2.42) ^c	0.719 ± 0.010	0.033 (0.027–0.038) ^c	0.027 (0.022–0.032) ^c
Unsure of the exposure trimester			3795	135 (3.6)	1.31 (1.11–1.65) ^b	1.21 (0.98–1.48)	0.645 ± 0.007	0.012 (0.009–0.016) ^c	0.008 (0.004–0.012) ^c

Notes: ^† Model was unadjusted for any confounding variables. ^‡ Multiple logistic regression model was used, while adjusting for gender, preterm birth, birth asphyxiation, fetal growth restriction, family income, paternal and maternal education, paternal and maternal age at childbirth. ^§ Hierarchical linear regression model was used, while adjusting for gender, preterm birth, birth asphyxiation, fetal growth restriction, family income, paternal and maternal education, paternal and maternal age at childbirth. ^¶ β was the coefficient for ETS exposure variable in the hierarchical linear regression model, where the dependent variable took the form of log (hyperactivity score + 1). ^a p < 0.05; ^b p < 0.005; ^c p < 0.001.