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Table 1 Selected baseline characteristics of study participants by case (invasive breast cancer) and control status

From: Novel polymorphisms in caspase-8 are associated with breast cancer risk in the California Teachers Study

Variables

Cases (n = 1353)

%

Controls (n = 1384)

%

Chi square p-value

Age, years (mean ± SD)

55.0 ± 9.4

 

56.1 ± 9.5

  

First-degree family history of breast cancer

    

0.0046

á…ŸNo

1086

80.3

1158

83.7

 

á…ŸYes

237

17.5

187

13.5

 

Body mass index, kg/m2

    

0.21

ᅟ < 25

779

57.6

759

54.8

 

á…Ÿ25 to 29.9

384

28.4

385

27.8

 

ᅟ ≥ 30

160

11.8

192

13.9

 

Age at menarche, years

    

0.45

ᅟ < 13

700

51.7

695

50.2

 

ᅟ ≥ 13

638

47.2

671

48.5

 

Parity

    

0.12

á…Ÿ0

289

21.4

280

20.2

 

á…Ÿ1

173

12.8

165

11.9

 

á…Ÿ2

481

35.6

476

34.4

 

á…Ÿ3

275

20.3

277

20.0

 

ᅟ ≥ 4

120

8.9

165

11.9

 

Age at first full-term pregnancy, years

   

0.38

ᅟ < 21

89

8.5

96

8.9

 

á…Ÿ21-24

325

31.0

343

31.7

 

á…Ÿ25-29

415

39.6

451

41.6

 

á…Ÿ30-34

169

16.1

155

14.3

 

ᅟ ≥ 35

51

4.9

38

3.5

 

Hormone therapy (HT) at baseline

    

0.0001

á…ŸPremenopausal

364

26.9

346

25.0

 

á…ŸPostmenopausal - never used HT

113

8.4

150

10.8

 

á…ŸPostmenopausal - past use HT

76

5.6

115

8.3

 

á…ŸPostmenopausal - current estrogen use

200

14.8

249

18.0

 

ᅟPostmenopausal - current estrogen + progestin use

402

29.7

335

24.2

 

á…ŸUnknown

198

14.6

189

13.7

 

Strenuous or moderate physical activity, during 3 years before baseline

   

0.0035

ᅟ0-0.50 hrs/week/year

290

21.4

289

20.9

 

ᅟ0.51-4.00 hrs/week/year

632

46.7

572

41.3

 

ᅟ4.01-24 hrs/week/year

424

31.3

514

37.1

 

Grams per day of alcohol, during year before baseline

    

0.0006

á…ŸNondrinkers

334

24.7

379

27.4

 

ᅟ < 20 g/d

806

59.6

836

60.4

 

ᅟ > =20 g/d

165

12.2

109

7.9

 
  1. Table does not list small percentages of missing values for some factors