. Author manuscript; available in PMC: 2023 Apr 11.

Published in final edited form as: J Epidemiol Community Health. 2010 Jan;64(1):82–88. doi: 10.1136/jech.2009.089334

Table 2.

ORs for behaviour problems at age 3 by maternal smoking status during pregnancy

Behaviour problems	Never smoked	Quit smoking	Light smoker	Heavy smoker
Behaviour problems	Never smoked	OR (95% CI)	OR (95% CI)	OR (95% CI)
Boys
Unadjusted
Conduct	Ref	1.54 (1.16 to 2.04)^**	2.66 (2.07 to 3.42)^*	4.50 (3.60 to 5.65)^*
Hyperactivity–inattention	Ref	1.09 (0 .86 to 1.39)	1.64 (1.35 to 2.02)^*	2.21 (1.74 to 2.79)^*
Fully adjusted
Conduct	Ref	1.21 (0.83 to 1.78)	1.44 (1.01 to 2.06)^***	1.80(1.28 to 2.54)^**
Hyperactivity–inattention	Ref	0.94 (0.67 to 1.32)	1.56 (1.12 to 2.15)^**	1.62 (1.13 to 2.33)^**
Girls
Unadjusted
Conduct	Ref	1.14 (0.83 to1.55)	2.28 (1.70 to 3.07)^*	3.45 (2.69 to 4.44)^*
Hyperactivity–inattention	Ref	1.31 (0.98 to 1.73)	1.80 (1.36 to 2.38)^*	2.28 (1.71 to 3.04)^*
Fully adjusted
Conduct	Ref	0.61 (0.39 to 0.97)^***	1.06 (0.70 to 1.63)	1.34 (0.88 to 2.03)
Hyperactivity–inattention	Ref	0.96 (0.66 to 1.41)	1.28 (0.90 to 1.81)	1.17 (0.79 to 1.72)

Differences statistically significant at *p<0.001, **p<0.01, ***p<0.05.

Conduct problems = scores of 6 or above out of 10 (top 10.3% male, 8.7% female) Hyperactivity–inattention problems = scores of 7 or above (top 14.9% male, 9.2% female)