. 2023 Sep 11;103(4):669–683. doi: 10.1111/aogs.14677

TABLE 3.

Associations between incidence of cancer during first year post‐delivery and calendar year, age, parity, immigrant status, education, smoking and BMI by cancer type in Sweden 1990–2017.

	All tumor types			Malignant melanoma			Breast			Cervix
	n	IRR ^a	95% CI	n	IRR ^a	95% CI	n	IRR ^a	95% CI	n	IRR ^a	95% CI
Year at delivery/diagnosis
1990–1994	369	1.00	Ref	62	1.00	Ref	74	1.00	Ref	39	1.00	Ref
1995–1999	307	1.01	0.87–1.18	49	0.95	0.65–1.38	58	0.88	0.62–1.24	32	1.02	0.64–1.63
2000–2004	352	1.05	0.91–1.22	63	1.10	0.77–1.56	60	0.77	0.55–1.08	54	1.61	1.06–2.44
2005–2009	468	1.22	1.06–1.40	78	1.20	0.85–1.68	113	1.20	0.89–1.62	54	1.48	0.97–2.26
2010–2014	600	1.49	1.30–1.70	127	1.89	1.38–2.59	130	1.28	0.96–1.73	75	2.03	1.36–3.03
2015–2017	341	1.39	1.20–1.62	75	1.88	1.33–2.66	65	1.05	0.74–1.48	47	2.13	1.38–3.30
			P < 0.0001			P < 0.0001			P = 0.0136			P = 0.0006
Age at delivery/diagnosis
15–24	161	0.33	0.27–0.39	22	0.28	0.18–0.45	4	0.04	0.02–0.11	18	0.22	0.13–0.36
25–29	525	0.55	0.49–0.62	110	0.64	0.50–0.82	58	0.30	0.22–0.40	71	0.48	0.36–0.64
30–34	929	1.00	Ref	171	1.00	Ref	193	1.00	Ref	139	1.00	Ref
35–39	617	1.44	1.29–1.59	117	1.52	1.20–1.93	181	2.00	1.63–2.46	63	0.98	0.73–1.33
40–44	205	2.43	2.09–2.84	34	2.34	1.61–3.40	64	3.58	2.68–4.77	10	0.79	0.42–1.51
			P < 0.0001			P < 0.0001			P < 0.0001			P < 0.0001
Parity prior to current delivery
0	921	1.00	Ref	186	1.00	Ref	155	1.00	Ref	115	1.00	Ref
1	922	0.96	0.88–1.06	181	0.93	0.76–1.15	198	1.04	0.84–1.28	117	0.98	0.75–1.27
2+	594	0.90	0.80–1.00	87	0.72	0.55–0.95	147	0.95	0.75–1.21	69	0.89	0.64–1.23
Not counting index birth			P = 0.1555			P = 0.0607			P = 0.7523			P = 0.7609
Immigrant status
Non‐immigrant	1998	1.00	Ref	424	1.00	Ref	391	1.00	Ref	262	1.00	Ref
Immigrant	439	0.83	0.75–0.92	30	0.27	0.19–0.39	109	1.07	0.86–1.33	39	0.53	0.38–0.75
Imputed	0			0			0			0
			P = 0.0006			P < 0.0001			P = 0.5704			P = 0.0004
Education
<10 years	239	0.98	0.84–1.13	27	0.85	0.56–1.29	38	0.82	0.57–1.18	36	1.20	0.81–1.75
10–13 years	995	1.00	Ref	172	1.00	Ref	189	1.00	Ref	140	1.00	Ref
Undergraduate	361	0.95	0.84–1.08	84	1.25	0.96–1.63	81	0.98	0.75–1.27	35	0.67	0.46–0.97
Postgraduate	788	0.92	0.83–1.02	167	1.03	0.81–1.30	182	0.92	0.74–1.15	87	0.70	0.52–0.93
Imputed	54			4			10			3
			P = 0.4208			P = 0.2622			P = 0.6897			P = 0.0159
Cigarette smoking
No	1930	1.00	Ref	377	1.00	Ref	414	1.00	Ref	237	1.00	Ref
Yes	350	1.02	0.91–1.14	50	0.84	0.62–1.14	51	0.78	0.58–1.05	52	1.08	0.79–1.48
Imputed	157			27			35			12
			P = 0.7710			P = 0.2583			P = 0.1007			P = 0.6298
Pre‐pregnancy BMI
<18.5	47	1.11	0.82–1.48	6	0.76	0.33–1.71	8	1.09	0.52–2.27	7	1.30	0.61–2.77
18.5–24.9	1243	1.00	Ref	244	1.00	Ref	244	1.00	Ref	158	1.00	Ref
25.0–29.9	505	0.98	0.88–1.09	96	1.01	0.78–1.30	103	0.99	0.78–1.25	71	1.09	0.83–1.44
30.0+	205	0.86	0.74–1.00	36	0.84	0.58–1.20	46	0.97	0.71–1.32	28	0.90	0.60–1.35
Imputed	437			72			99			37
			P = 0.2118			P = 0.6963			P = 0.9908			P = 0.7497
Cases with information imputed, total	485			81			108			43

^{^a}

Model included year, age, parity, immigration status, education, smoking and body mass index (BMI). Education, smoking and BMI imputed using MICE, 10 cycles of chained equations and 30 sets.