Table 3.

Odds ratios^† and 95% CIs of breast cancer within tertiles of human chorionic gonadotropin and free β-human chorionic gonadotropin concentrations and on a continuous scale.

	Tertiles				Continuous
	Tertile 1	Tertile 2	Tertile 3	p-trend	Per unit increase	p-value
Total hCG
Cases/controls (n)	66/96	40/95	53/95	–	159/286	–
Crude total hCG	1.0 (ref)	0.60 (0.37–0.99)	0.79 (0.49–1.27)	0.31	0.89 (0.64–1.24)	0.49
Adjusted for free β-hCG	1.0 (ref)	0.63 (0.37–1.06)	0.85 (0.49–1.47)	0.56	0.97 (0.65–1.43)	0.86
Free β-hCG
Cases/controls (n)	53/96	61/95	45/95	–	159/286	–
Crude free β-hCG	1.0 (ref)	1.16 (0.47–2.85)	0.85 (0.33–2.18)	0.34	0.92 (0.77–1.09)	0.31
Adjusted for total hCG	1.0 (ref)	1.17 (0.47–2.91)	0.89 (0.34–2.33)	0.43	0.92 (0.75–1.13)	0.44
Ratio of total hCG to free β-hCG
Cases/controls (n)	67/96	43/95	49/95	–	159/286	–
Total hCG/free β-hCG	1.0 (ref)	0.64 (0.40–1.02)	0.74 (0.46–1.19)	0.18	1.01 (0.97–1.06)	0.58

^†Crude odds ratios presented. Adjustments for potential confounders (smoking and child gender) did not alter risk estimates by up 5%.

hCG: Human chorionic gonadotropin; ref: Reference.