Table II.

Relationship of selected demographic and other factors to endometrial cancer risk.

	Endometrial cancer (n = 118)	Non-cases (n = 9714)	HRa	95% CI
Race
White	91	7376	1.00	Referent
African–American	4	441	0.65	0.24–1.81
Other	7	525	1.04	0.48–2.25
Unknown	16	1372	0.83	0.49–1.42
Reproductive status at the first clinic visit
Gravid	60	5589	1.00	Referent
Nulligravid	58	4125	1.31	0.91–1.88
Reproductive status at follow-up
Gravid	79	6897	1.00	Referent
Nulligravid	23	1357	1.54	0.53–1.55
Unknown	16	1460	0.90	0.96–2.44
Number of births at follow-up
≥3	9	998	1.00	Referent
2	16	1718	1.09	0.48–2.48
1	23	1465	1.77	0.82–3.84
0	35	2037	2.08	1.00–4.33
Unknown	35	3496	1.09	0.52–2.26
Age at menarche
<12	30	1891	1.00	Referent
12	34	2643	0.82	0.50–1.33
13	30	2902	0.66	0.40–1.09
≥14	17	1999	0.51	0.28–0.93
Unknown	7	279	1.68	0.73–3.89
Ever use of oral contraceptives
No	14	915	1.00	Referent
Yes	67	5862	0.77	0.43–1.37
Unknown	37	2937	0.82	0.44–1.52
Ever use of menopausal hormones
No	25	2046	1.00	Referent
Yes	36	2605	1.19	0.71–1.99
Unknown	57	5063	0.95	0.59–1.53
BMI at the first clinic visit (quartiles, kg/m2)
<23.0	47	4854	1.00	Referent
23.0–24.9	10	1078	0.99	0.50–1.97
25.0–29.9	11	1010	1.15	0.59–2.23
≥30.0	21	451	5.18	3.06–8.75
Unknown	29	2321	1.55	0.92–2.62
BMI at age 40 (quartiles, kg/m2)
<23.0	21	2207	1.00	Referent
23.0–24.9	12	1080	1.20	0.59–2.44
25.0–29.9	17	916	2.00	1.05–3.81
≥30.0	11	422	2.90	1.39–6.04
Unknown	57	5089	1.20	0.72–2.00
Cause of infertilityb
Endometriosis	22	2181	0.90	0.54–1.49
Anovulation	35	2723	1.15	0.77–1.72
Tubal disease/pelvic adhesions	39	3457	0.98	0.65–1.47
Male factor	39	2176	1.63	1.07–2.50
Cervical disorder	7	605	0.87	0.39–1.93
Uterine disorder	10	1036	0.84	0.43–1.65

^aHRs adjusted for study site and calendar year of the first infertility evaluation.

^bRisks are relative to women with no evidence of the condition, taking into account the adequacy of the evaluation. Conditions are not mutually exclusive, i.e. women could be classified as having more than one cause of infertility.