Table V.

Risk of colorectal and thyroid cancer for ART women compared with non-ART women, stratified analyses.

	Colorectal cancer (C18-20)					Thyroid cancer (C73)
	ART	Non-ART	HR	Lower bound	Upper bound	ART	Non-ART	HR	Lower bound	Upper bound
	n	n				n	n
Number of cancers during the observational period	25	1364				13	919
Crude risk	22	1364	1.36	0.89	2.07	13	919	1.14	0.66	1.97
Adjusted riska	22	1364	1.31	0.85	2.01	13	919	1.15	0.66	2.00
Excl. cancer during the first yearb	22	1354	1.34	0.87	2.06	13	894	1.18	0.68	2.06
Parity at entry
P0	20	659	1.43	0.91	2.25	12	640	1.07	0.60	1.91
P1+	2	705	0.90	0.22	3.60	1	279	0.97	0.13	6.93
Total	22	1364				13	919
Parity at exit
One	9	183	1.13	0.57	2.23	3	201	0.50	0.15	1.55
Two	10	572	1.41	0.75	2.65	7	403	1.59	0.75	3.39
Three or more	3	609	1.81	0.58	5.64	3	315	2.60	0.83	8.15
Total	22	1364				13	919
Method of ART
IVF	16	1364	1.27	0.77	2.10	9	919	1.15	0.59	2.23
ICSI	2	1364	0.95	0.24	3.80	2	919	0.87	0.22	3.51
Other	4	1364	1.86	0.69	4.98	2	919	1.59	0.40	6.40
Total	22					13
Duration of follow-up, years
<1 year	0	10	NA	–	–	0	26	NA	–	–
1–5	6	81	2.27	0.96	5.41	3	186	0.82	0.26	2.61
>5–10	5	158	1.13	0.46	2.82	3	238	0.81	0.26	2.58
>10	11	1115	1.16	0.64	2.12	7	469	1.84	0.87	3.93
Total	22	1364				13	919

^aHazard ratios are adjusted for attained age, age at start of follow-up, parity, region of residence and calendar period.

^bThose with an index cancer diagnosed within the first year of follow-up were omitted from this analysis.