Table 1

Baseline characteristics for 70,575 women in the PLCO Cancer Screening Trial Cohort.

Number

%


Age at baseline

55–59

24,381

34.6

60–64

21,405

30.3

65–69

15,405

21.8

70–74

9,384

13.3

Race/ethnicity

White

62,425

88.5

African-American

4,063

5.8

Asian/Pacific Islander

2,754

3.9

Other*

1,333

1.9

Education

Less than H.S.

4,598

6.5

Completed H.S.

28,588

40.5

Beyond H.S.

37,215

52.7

Unknown

174

0.3

Marital status

Married or living as married

48,749

69.1

Widowed

9,700

13.7

Divorced or separated

9,616

12.7

Never married/missing

2,510

4.5

Mother or sister with breast cancer

No

57,214

81.1

Yes

9,692

13.7

Unknown

3,669

5.2

Age at menarche

< 12

14,259

20.2

12 – 13

37,816

53.6

14 – 15

15,105

21.4

≥ 16

3,208

4.6

Missing

187

0.3

Years of oral contraceptive use

None

32,170

45.6

< 1 year

10,219

14.5

2 – 3 years

7,636

10.8

4 – 5 years

5,208

7.4

6 – 9 years

6,303

8.9

≥ 10 years

8,830

12.5

Missing

209

0.3

Parity and age at first birth

Nulliparous

6,454

9.1

1–2

< 20 years

2,499

3.5

20–24 years

9,336

13.2

25–29 years

6,629

9.4

30–34 years

2,405

3.4

≥ 35 years

1,021

1.5

3–4

< 20 years

5,721

8.1

20–24 years

16,227

23.0

25–29 years

5,942

8.4

30–34 years

1,020

1.5

≥ 35 years

343

0.5

≥ 5

< 20 years

3,818

5.4

20–24 years

7,162

10.2

25–29 years

1,506

2.1

30–34 years

193

0.3

≥ 35 years

194

0.3

Missing or unknown

105

0.2

Menopause Type

Natural

43,572

61.7

Surgical

23,312

3233.0

Radiation or medications

2,346

3.3

Missing

1345

41.9

Age at Natural Menopause

< 45 years

4,468

6.3

45–49 years

11,175

15.8

50–54 years

22,134

31.4

55+ years

5,709

8.1

Missing

86

0.1

Menopausal hormone therapy use

None

23,262

33.0

Former use

11,435

16.2

Current use, ≤ 5 years

11,546

16.4

Current use, > 5 years

23,712

33.6

Missing

620

0.9

Body Mass Index (BMI; kg/m2)

< 18.5

892

1.3

18.5 – 24.9

27,251

38.6

25 – 29

24,214

34.3

30 – 34.9

11,102

15.7

≥ 35

6,297

8.9

Missing

819

1.2


*Other race/ethnicity includes Hispanic, American Indian, and missing/unknown.

Lacey et al. BMC Cancer 2009 9:84   doi:10.1186/1471-2407-9-84

Open Data