Table 4.

Maternal smoking by DDC haplotypes among 1177^a case- and control-mothers.

			OR of smokingc			No. of cigarettes smoked
Haplotypeb	Haplotype frequency (%)	One or two copies	OR	95% CI	P valuee	Coefficientd	95% CI	P valuee
a-t-T-a-c	15	One	1.1	0.9–1.5	0.48	0.5	−0.8–1.7	0.74
		Two	0.8	0.4–1.6		0.1	−3.3–3.5
G-t-T-a-c	4	One	0.7	0.5–1.1	<0.001	0.0	−1.4–1.4	0.90
		Two	29.2	5.8–147.5		0.8	−2.7–4.3
G-G-c-G-c	7	One	1.5	1.0–2.1	0.13	−0.9	−2.4–0.6	<0.001
		Two	1.0	0.1–8.5		2.9	1.6–4.2
G-G-T-G-c	12	One	1.0	0.8–1.4	0.89	−0.1	−1.4–1.1	0.94
		Two	1.2	0.5–2.8		−0.4	−2.9–2.0
G-G-T-a-T	4	One	1.1	0.6–2.1	0.90	−2.5	−4.4–−0.7	0.03
		Two	1.0	0.2–5.5		−1.7	−8.6–5.2
G-G-c-G-T	36	One	Ref.	-	-	Ref.	-	-
		Two
G-G-T-G-T	13	One	1.1	0.8–1.5	0.41	−0.8	−2.0–0.4	0.38
		Two	0.5	0.2–1.7		0.5	−5.4–6.4
G-t-T-G-T	7	One	1.2	0.8–1.7	0.59	−0.2	−1.5–1.1	0.06
		Two	1.2	0.2–6.2		−2.8	−5.0-−0.5

^aHaplotypes could be predicted for 1177 mothers from the offspring-parent trios using HAPLIN.

^bHaplotypes of rs2060762-rs3757472-rs1451371-rs3735273-rs921451.

^cOdds ratio of maternal smoking during the first trimester of pregnancy estimated by frequency-weighted logistic regression, using the probability distribution of possible haplotypes for each mother as predicted by HAPLIN from the offspring-parent trios.

^dRegression analysis of number of cigarettes smoked per day during first trimester of pregnancy by frequency-weighted linear regression, using the probability distribution of possible haplotypes for each mother as predicted by HAPLIN from the offspring-parent trios.

^eP-values for effect of one or two copies of the haplotype.

Abbreviations: DDC, dopa decarboxylase; OR, odds ratio; CI, confidence interval; ref, reference haplotype.