Table 2.

Comparison of mother’s exposure to ETS during pregnancy and socio-demographic characteristics between children with and without externalizing behavior problems

Variables	Externalizing behavior problems?		p value
	No (n = 519)	Yes (n = 127)
Mother exposed to ETS during pregnancy
No	340 (65.5)	66 (51.9)	0.0046
Yes	179 (34.5)	61 (48.0)
Sex
Boy	275 (52.9)	70 (55.1)	0.66
Girl	244 (47.1)	57 (44.9)
Sibling
No	394 (75.9)	93 (73.2)	0.53
Yes	125 (24.1)	34 (26.8)
School area
City	211 (40.7)	45 (35.4)	0.45
Suburban	195 (37.6)	55 (43.3)
Rural	113 (21.7)	27 (21.3)
Blood lead level (μg/dL, median and range)	5.9 (1.8–27.5)	5.8 (2.2–32.0)	0.12
Father’s education
Less than high school	193 (37.2)	48 (37.8)	0.93
High school	158 (30.4)	40 (31.5)
College and University	168 (32.4)	39 (30.7)
Father’s occupation
Unemployed	12 (2.3)	6 (4.7)	0.32
General labor	266 (51.2)	66 (51.9)
Technician/professional	211 (40.7)	51 (40.2)
Other	30 (5.8)	4 (3.2)
Father smoked after the child was born
Missing	10 (1.9)	3 (2.4)	0.87
No	116 (22.3)	24 (18.9)
<10 cigarettes/day	276 (53.2)	73 (57.5)
10–20 cigarettes/day	91 (17.5)	20 (15.8)
20+ cigarettes/day	26 (5.0)	7 (5.5)
Mother’s age when the child was born
<25	158 (30.4)	40 (31.5)	0.77
25–30	323 (62.2)	80 (62.9)
30+	38 (7.3)	7 (5.5)
Mother’s education
Less than high school	239 (46.1)	65 (51.2)	0.11
High school	148 (28.5)	41 (32.3)
College and University	132 (25.4)	21 (16.5)
Mother’s occupation
Unemployed	24 (4.6)	7 (5.5)	0.37
General labor	208 (40.1)	59 (46.5)
Technician/professional	176 (33.9)	33 (25.9)
Other	111 (21.4)	28 (22.1)
Parental psychopathologic problem?
No	493 (95.0)	118 (92.9)	0.35
Yes	26 (5.0)	9(7.1)
Parental divorce
Missing	26 (5.0)	7 (5.5)	0.84
No	474 (91.3)	114 (89.8)
Yes	19 (3.7)	6 (4.7)

Numbers in parenthesis are percentages expect for blood lead level.