Perinatal and early life risk factors for inflammatory bowel disease

Table 1 Age at first day case or inpatient admission for offspring with inflammatory bowel disease n (%)

	Age at first hospitalisation (yr) with inflammatory bowel disease						Total
	< 1	1-4	5-9	10-14	15-19	20-29
Crohn’s disease
Male	1 (2)	1 (2)	4 (7)	11 (20)	18 (33)	20 (36)	55 (100)
Female	0	0	0	11 (19)	19 (32)	29 (49)	59 (100)
Total	1 (1)	1 (1)	4 (4)	22 (19)	37 (32)	49 (43)	114 (100)
Ulcerative colitis
Male	0	1 (3)	2 (7)	2 (7)	7 (24)	17 (59)	29 (100)
Female	0	1 (3)	3 (8)	6 (16)	11 (30)	16 (43)	37 (100)
Total	0	2 (3)	5 (8)	8 (12)	18 (27)	33 (50)	66 (100)

Table 2 Associations between maternal characteristics and inflammatory bowel disease in the child

Maternal characteristics	No. of births	Crohn’s disease			Ulcerative colitis
		No. of cases	Percent	P-value1	No. of cases	Percent	P-value2
Maternal age (yr)				0.19			0.90
14-24	86 544	41	0.047%		21	0.024%
25-34	142 939	59	0.041%		40	0.028%
35-49	18 852	14	0.074%		5	0.027%
Maternal Crohn’s disease or ulcerative colitis				0.011a			1.00
No	248 132	112	0.045%		66	0.027%
Yes	530	2	0.380%		0
Maternal social class				0.10			0.12
I & II	68 244	21	0.031%		12	0.018%
III	86 869	54	0.062%		32	0.037%
IV & V	35 510	22	0.062%		11	0.031%
Marital status				0.081			0.042a
Married	224 261	109	0.049%		65	0.029%
Not married	23 939	5	0.021%		1	0.004%
Maternal smoking during pregnancy				0.054			0.73
No	110 961	27	0.024%		18	0.016%
Yes	34 245	16	0.047%		4	0.012%
Maternal ABO blood group				0.84			0.81
A	101 010	44	0.044%		26	0.026%
O	105 391	49	0.046%		30	0.028%
Maternal rhesus Status				0.96			0.97
Negative	39 805	18	0.045%		10	0.025%
Positive	196 652	87	0.044%		53	0.027%
Pre-eclampsia				0.29			1.00
No	224 360	99	0.044%		60	0.027%
Yes	24 250	15	0.062%		6	0.025%
Parity				0.23			0.59
O	104 210	41	0.039%		25	0.024%
1+	144 214	73	0.051%		41	0.028%

^1,2P-values obtained through χ² tests, with Yates continuity corrections;

¹Comparing those with Crohn’s disease with those without known inflammatory bowel disease (IBD);

²Comparing those with ulcerative colitis with those without known IBD.

^aP < 0.05.

Table 3 Associations between characteristics of the births and inflammatory bowel disease in the child

Characteristics of the births	No. of births	Crohn’s disease			Ulcerative colitis
		No. of cases	Percent	P-value1	No. of cases	Percent	P-value2
Presentation at delivery				0.47			1.00
Vertex	158 302	52	0.033%		26	0.016%
Other	8311	1	0.012%		1	0.012%
Caesarean birth				0.72			0.81
No	223 793	104	0.046%		63	0.028%
Yes	18 025	10	0.055%		3	0.017%
Forceps delivery				1.00			0.95
No	210 100	99	0.047%		58	0.028%
Yes	31 718	15	0.047%		8	0.025%
Sex				0.56			0.28
Male	127 829	55	0.043%		29	0.023%
Female	120 823	59	0.049%		37	0.031%
No. of babies				0.53			0.37
1	243 269	113	0.046%		63	0.026%
2+	5390	1	0.019%		3	0.056%
Gestational age (wk)				0.72			0.60
24-37	21 912	8	0.037%		5	0.023%
38-41	173 868	82	0.047%		51	0.029%
42-47	20 567	12	0.058%		3	0.014%
Birth weight (g)				0.72			0.46
1000-2999	58 553	31	0.053%		14	0.024%
3000-3499	168 149	73	0.043%		43	0.026%
3500+	21 151	10	0.047%		9	0.043%
Head circumference (cm)				0.34			0.99
< 34	34 681	13	0.037%		6	0.017%
34-35	39 128	15	0.038%		6	0.015%
35-36	38 528	6	0.016%		7	0.018%
36+	51 035	14	0.027%		7	0.014%
Breastfeeding				0.89			0.67
Artificial	50 966	17	0.033%		10	0.020%
Breastfed	117 364	36	0.031%		18	0.015%
Apgar 1 score				0.34			0.99
1-5	21 356	14	0.066%		6	0.028%
6-8	64 469	27	0.042%		16	0.025%
9-10	140 267	57	0.041%		37	0.026%
Apgar 5 score				0.87			0.61
1-5	884	0			1	0.11%
6-8	4229	2	0.047%		0
9-10	148 835	43	0.029%		23	0.015%

^1,2P-values obtained through χ² tests, with Yates continuity corrections;

¹Comparing those with Crohn’s disease with those without known inflammatory bowel disease (IBD);

²Comparing those with ulcerative colitis with those without known IBD.

Table 4 Perinatal factors with significant, independent effect on Crohn’s disease in the child

Perinatal risk factor	Odds ratio	95% CI
Maternal age (yr)
14-34	1.00	Ref.
35-49	4.81	2.32-9.98
Maternal smoking during pregnancy
No	1.00	Ref.
Yes	2.04	1.06-3.92