Table 2.

Select Characteristics of Simple Ovarian Cyst Study Cohort^*

		Number	%
Total Study Population		15735	100.0
Age
	55–59	5679	36.1
	60–64	4994	31.7
	65–69	3260	20.7
	70–74	1802	11.5
Race/Ethnicity
	White	14068	89.4
	Black	508	3.2
	Hispanic	218	1.4
	Asian	717	4.6
	Pacific Islander	84	0.5
	American Indian	34	0.2
	Missing	106	0.7
Education
	<12 years	796	5.1
	12 yrs/Completed High School	6204	39.4
	Some College	3526	22.4
	College Graduate	2602	16.5
	Post Graduate	2492	15.8
	Missing	115	0.7
Cigarette Use
	Never Smoked	8876	56.4
	Current Smoker	1348	8.6
	Former Smoker	5406	34.4
	Missing	105	0.7
First Degree Family History of Breast Cancer
	No	12613	80.2
	Yes	2238	14.2
	Unknown	541	3.4
	Missing	343	2.2
Total Years of Oral Contraceptive use
	0	7178	45.6
	<1	2214	14.1
	2–3	1731	11.0
	4–5	1174	7.5
	6–9	1421	9.0
	10+	1888	12.0
	Missing	129	0.8
Age at First Pregnancy
	Never pregnant	1105	7.0
	less than 20	3308	21.0
	20–24	7313	46.5
	25–29	2958	18.8
	30+	907	5.8
	Missing	144	0.9
Number of Pregnancies
	Never pregnant	1105	7.0
	1	892	5.7
	2	2800	17.8
	3–4	6481	41.2
	5–9	4046	25.7
	10+	277	1.8
	Missing	134	0.9
Hormone Replacement
	No	5437	34.6
	Yes	10131	64.4
	Don't Know	52	0.3
	Missing	115	0.7
Age at Menopause
	<40	1576	10.0
	40–44	1730	11.0
	45–49	3536	22.5
	50–54	6579	41.8
	55+	2072	13.2
	Missing	242	1.5
Previous Gynecologic Surgery
	No	9406	59.8
	Yes	6159	39.1
	Don't Know	32	0.2
	Missing	138	0.9
History of Benign Ovarian Tumors or Cysts
	No	14101	89.6
	Yes	1236	7.9
	Missing	398	2.5
Use of NSAIDs or aspirin
	No	6798	43.2
	Yes	8769	55.7
	Missing	168	1.1
History of Infertility
	No	13374	85.0
	Yes	2218	14.1
	Missing	143	0.9

NSAID - Non-steroidal anti-inflammatory drugs

^*PLCO Trial women in intervention arm with both ovaries visualized by transvaginal ultrasound one or more times from baseline (T0) through the Year 3 (T3) screening