Maternal occupational exposure and oral clefts in offspring

Spinder, Nynke; Bergman, Jorieke E. H.; Boezen, H. Marike; Vermeulen, Roel C. H.; Kromhout, Hans; de Walle, Hermien E. K.

doi:10.1186/s12940-017-0294-5

Environmental Health

Table 1 Baseline characteristics of cases (all oral clefts, cleft palate (CP), cleft lip with/without cleft palate CL(P)) compared with two malformed control groups

From: Maternal occupational exposure and oral clefts in offspring

	Chromosomal controls^a		Non-chromosomal controls^b		All oral cleft				CP				CL(P)
	n	%	n	%	n	%	p-value^c	p-value^d	n	%	p-value^c	p-value^d	n	%	p-value^c	p-value^d
	1135		4356		387				124				263
Child sex							<0.001	0.21			0.83	0.43			<0.001	0.02
Boy	547	48.2	2373	54.5	227	58.7			61	49.2			166	63.1
Girl	588	51.8	1970	45.3	160	41.3			63	50.8			97	36.9
Unknown	0		9		0				0				0
Number of babies/foetuses delivered							0.31	0.98			0.09	0.30			0.86	0.50
1	1089	96.0	4104	94.8	366	94.8			115	92.7			251	95.8
> 1	45	4.0	223	5.2	20	5.2			9	7.3			11	4.2
Unknown	1		25		1				0				1
Previous births							0.24	0.01			0.60	0.11			0.36	0.05
0	476	42.3	2313	53.2	180	46.6			57	46.0			123	46.9
1	461	40.9	461	34.6	141	36.5			45	36.3			96	36.6
≥ 2	189	16.8	189	12.1	65	16.8			22	17.7			43	16.4
Unknown	9		8		1				0				1
Maternal age at delivery							<0.001	0.66			0.09	0.40			<0.001	0.66
15–19	4	0.4	14	0.3	2	0.5			0				2	0.8
20–24	55	4.8	369	8.5	24	6.2			8	6.5			16	6.1
25–29	299	26.3	1458	33.5	132	34.3			43	35.0			89	34.0
30–34	407	35.9	1770	40.7	154	40.0			47	38.2			107	40.8
35–39	284	25.0	651	15.0	63	16.4			19	15.4			44	16.8
> 40	86	7.6	86	2.0	10	2.6			6	4.9			4	1.5
Unknown	0		0		2				1				1
Pre-pregnancy BMI (kg/m²)							0.03	0.21			0.19	0.49			0.09	0.29
< 18.5	30	2.8	112	2.7	12	3.2			2	1.7			10	3.9
18.5–25	721	66.3	2713	64.6	224	59.1			71	59.2			153	59.1
25–30	258	23.7	975	23.2	101	26.6			33	27.5			68	26.3
> 30	78	7.2	402	9.6	42	11.1			14	11.7			28	10.8
Unknown	48		150		8				4				4
Education level							0.01	0.84			0.59	0.72			0.01	0.56
Low	151	13.8	545	12.8	51	13.5			15	12.4			36	14.0
Middle	462	42.2	2137	50.3	193	51.1			57	47.1			136	52.9
High	481	44.0	1568	36.9	134	35.4			49	40.5			85	33.1
Unknown	41		102		9				3				6
Smoking during pregnancy							0.02	0.47			0.72	0.49			0.01	0.18
No	89	81.0	3321	77.0	291	75.4			98	79.7			193	73.4
Yes	210	19.0	992	23.0	95	24.6			25	20.3			70	26.6
Unknown	28		39		1				1				0
Alcohol during pregnancy							0.02	0.16			0.25	0.62			0.03	0.17
No	811	73.3	3276	76.1	306	79.3			96	78.0			210	79.8
Yes	296	26.7	1029	23.9	80	20.7			27	22.0			53	20.2
Unknown	28		47		1				1				0
Folic acid use							0.64	0.84			0.67	0.52			0.34	0.49
No	224	21.3	844	20.5	77	20.1			28	23.0			49	18.8
Yes	830	78.7	3265	79.5	306	79.9			94	77.0			212	81.2
Unknown	81		243		4				2				2
Fertility problems							0.39	0.29			0.73	0.11			0.19	0.84
No	889	81.0	3634	85.0	316	82.9			98	79.7			218	84.5
Yes	209	19.0	643	15.0	65	17.1			25	20.3			40	15.5
Unknown	37		75		6				1				5
Positive family history^e							0.003	0.08			0.17	0.60			0.005	0.07
No	960	85.0	3819	88.0	352	91.0			111	89.5			241	91.6
Yes	170	15.0	523	12.0	35	9.0			13	10.5			22	8.4
Unknown	4		10		0				0				0

^achromosomal/monogenic controls (not accompanied with oral clefts), ^bnon-chromosomal/non-monogenic malformed controls (not accompanied with oral clefts), ^c p-value comparing cases with chromosomal controls, ^d p-value comparing cases with non-chromosomal controls, ^epositive family history when first degree family member has same condition as child under study. Bold values represent significant values (p < 0.05)

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ISSN: 1476-069X

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