Table 1.

Characteristics of 552 endometrial cancer cases and 2,352 controls in the Iowa Women’s Health Study, 1986–2011

Characteristic	Women with endometrial cancer		Controls		p
	n a	%	n a	%
Education d					0.52
Less than high school	90	16.3	431	18.3
High school graduate	291	52.7	1,215	51.7
Some college	171	31.0	702	29.8
Smoking status b					0.05
Never	403	73.0	1,584	67.3
Former	103	18.7	523	22.2
Current	36	6.5	208	8.8
Alcohol intake					0.08
No	331	60.0	1,313	55.8
Yes	221	40.0	1,039	44.2
Physical activity					0.83
Inactive	263	47.6	1,073	45.6
Moderately active	146	26.4	652	27.7
Very active	133	24.1	588	25.0
Number of live births					<0.001
Nulliparous	69	12.5	217	9.2
1	70	14.6	163	7.7
2	131	27.3	534	25.3
3–4	209	43.5	912	43.1
≥ 5	70	14.6	505	23.9
Menopausal hormone use b					<0.001
Never	315	57.1	1,619	68.8
Former	93	16.8	166	7.1
Current	142	25.7	558	23.7
History of oral contraceptive use					0.006
Never	480	87.0	1,915	81.4
Ever	72	13.0	432	18.4
Diabetes b					<0.001
No	476	86.2	2,154	91.6
Yes	76	13.8	198	8.4
Hypertension b					0.007
No	270	48.9	1,299	55.2
Yes	282	51.1	1,053	44.8
CVD b					0.26
No	464	84.1	2,021	85.9
Yes	88	15.9	331	14.1
Histology c
Low-grade endometrioid adenocarcinoma	389	70.5	---	---
High-grade endometrioid adenocarcinoma	79	14.3	---	---
Non-endometrioid adenocarcinoma	63	11.4	---	---
Tumor summary stage
Localized	420	76.1	---	---
Regional	89	16.1	---	---
Distant	30	5.4	---	---
Surgery
No	16	2.9	---	---
Yes	524	94.9	---	---
Radiation
No	356	64.5	---	---
Yes	194	35.1	---	---

^aFrequencies may not add up to the total because of missing values

^bUpdated based on risk factor questionnaires closest to the reference date

^cTwenty-one endometrioid cases with missing grade could not be further categorized

^dAt baseline