Table 3.

Early Pregnancy hCG Concentrations (residuals and continuous) and Breast Cancer Risk by Age at First Term Birth and Diagnosis, and Time between First Birth and Diagnosis: Finnish Maternity Cohort

	Cases/Controls	OR*	ER+/PR+			ER−/PR−			phetǂ
			Cases/Controls	OR*	phet†	Cases/Controls	OR*	phet†
Overall	1,191/2,257	1.01 (0.91–1.12)	434/812	1.09 (0.90–1.34)		160/308	1.09 (0.79–1.50)		0.31
Age at first term birth					0.52			0.84
< 25 years	195/368	1.24 (0.96 – 1.61)	45/82	1.38 (0.79–2.41)		37/70	1.36 (0.77–2.38)		0.87
25 – 29 years	355/651	1.01 (0.83 – 1.23)	128/237	0.94 (0.67–1.32)		60/111	1.26 (0.76–2.07)		0.28
30 – 34 years	341/619	0.92 (0.76 – 1.13)	144/262	0.95 (0.69–1.31)		35/64	0.95 (0.47–1.94)		0.80
≥ 35 years	267/494	0.95 (0.75 – 1.21)	102/184	0.82 (0.54–1.24)		25/47	0.92 (0.40–2.13)		0.82
Age at diagnosis					0.41			0.80
< 40 years	508/973	0.96 (0.71–1.29)	148/280	1.05 (0.76 – 1.44)		96/186	1.19 (0.83–1.70)		0.38
40 – 49 years	592/1,119	0.99 (0.77–1.27)	244/459	1.10 (0.83 – 1.44)		58/111	1.17 (0.68–2.00)		0.58
≥ 50 years	91/165	1.32 (0.65–2.70)	42/73	1.41 (0.65 – 3.04)		6/11	3.02 (0.17–53.41)		0.57
Time between first term birth and diagnosis					0.25			0.38
< 5 years	143/275	0.89 (0.66 – 1.20)	41/76	0.82 (0.48–1.41)		27/52	1.31 (0.53–3.26)		0.38
5 – 9 years	370/705	1.01 (0.84 – 1.22)	131/247	0.94 (0.67–1.31)		55/108	1.04 (0.68–1.60)		0.70
10 – 14 years	424/811	0.99 (0.83 – 1.18)	152/292	0.94 (0.70–1.27)		57/109	1.32 (0.78–2.23)		0.27
≥ 15 years	254/465	1.15 (0.89 – 1.49)	110/197	1.34 (0.89–2.03)		21/39	1.54 (0.51–4.62)		0.82

^*per 1-unit increase in hCG residuals

^†p for heterogeneity across age at blood draw, age at diagnosis, or lag-time categories

^ǂp for heterogeneity comparing ER+/PR+ and ER−/PR− subtypes