Table 4.

Relationship of Clomiphene and Gonadotropin Use to Validated Breast Cancer Cases

	All Validated Cancers (n=696)			Validated Invasive Cancers (n=536)			Validated In Situ Cancers (n=160)
Selected Breast Cancer Risk Factors	# exposed cases	HR1	95% CI	# exposed cases	HR1	95% CI	# exposed cases	HR1	95% CI
Never Use of Clomiphene or Gonadotropins	417	1.00	referent	323	1.00	referent	94	1.00	referent
Clomiphene Use
Ever Use	264	1.04	0.89–1.22	202	1.04	0.87–1.24	62	1.05	0.76–1.45
Dosage (mg)
1–900	91	1.04	0.83–1.31	69	1.02	0.79–1.33	22	1.10	0.69–1.75
901–2250	70	0.85	0.66–1.10	52	0.83	0.61–1.11	18	0.94	0.56–1.56
≥2251	103	1.22	0.98–1.52	81	1.26	0.99–1.62	22	1.10	0.69–1.76
p for trend		0.40			0.41			0.80
Cycles
<6	160	0.94	0.78–1.13	119	0.91	0.73–1.12	41	1.05	0.72–1.52
6–11	69	1.16	0.90–1.50	52	1.15	0.86–1.55	17	1.20	0.71–2.02
≥12	35	1.45	1.02–2.05	31	1.69	1.17–2.46	4	0.68	0.25–1.87
p for trend		0.20			0.16			0.90
Gonadotropin Use
Ever Use	80	1.17	0.92–1.50	67	1.28	0.98–1.67	13	0.82	0.46–1.48
Dosage (ampules)
1–25	29	1.30	0.89–1.90	25	1.44	0.96–2.18	4	0.79	0.29–2.17
26–64	24	1.05	0.69–1.59	20	1.13	0.72–1.79	4	0.76	0.28–2.08
≥65	27	1.18	0.80–1.75	22	1.27	0.82–1.96	5	0.91	0.37–2.26
p for trend		0.30			0.18			0.78
Cycles
<6	65	1.16	0.89–1.51	55	1.27	0.95–1.70	10	0.77	0.40–1.49
≥6	15	1.26	0.75–2.12	12	1.32	0.74–2.36	3	1.07	0.34–3.39
p for trend		0.27			0.19			0.93
Combination of Clomiphene and Gonadotropins
Clomiphene only	199	1.00	0.85–1.19	146	0.96	0.79–1.17	53	1.14	0.81–1.60
Gonadotropins only	15	1.18	0.70–1.98	11	1.14	0.62–2.08	4	1.33	0.48–3.64
Both	65	1.17	0.90–1.53	56	1.31	0.99–1.75	9	0.71	0.35–1.41

¹HRs adjusted for study site, calendar year of first infertility evaluation, gravidity at first clinic visit.