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Table 1 Age-adjusted (≤45, 46+ years) characteristics at premenopausal mammography among 998 control women without breast cancer according to tertiles of absolute dense area, absolute non-dense area, and percent dense area

From: Nondense mammographic area and risk of breast cancer

 

Tertiles of absolute dense area in cm2

Characteristics

1 (< 42.5)

2 (< 79.3)

3 (< 300.1)

Number of controls

330

339

329

Age at mammography, years

48.7

47.3

45.8

Age at menarche, years

12.3

12.4

12.5

Family history of breast cancer, %

6.9

8.6

8.0

Nulliparous at the time of mammography, %

7.2

7.6

13.9

Number of children at mammography1

2.7

2.6

2.4

Age at first birth, years1

25.1

25.7

26.1

Body mass index at mammography, kg/m2

26.6

24.7

24.7

Alcohol use at mammography, g/day

4.1

5.5

4.6

Total area on mammogram, cm2

164

177

253

Absolute non-dense area on mammogram, cm2

139

117

131

 

Tertiles of absolute non-dense area in cm2

Characteristics

1 (< 69.5)

2 (< 145.1)

3 (< 482.6)

Number of controls

330

339

329

Age at mammography, years

47.3

47.4

47.2

Age at menarche, years

12.5

12.5

12.2

Family history of breast cancer, %

6.6

8.6

7.3

Nulliparous at the time of mammography, %

11.7

8.3

8.8

Number of children at mammography1

2.5

2.6

2.6

Age at first birth, years1

25.6

25.8

25.5

Body mass index at mammography, kg/m2

22.4

24.6

28.7

Alcohol use at mammography, g/day

5.8

4.7

3.9

Total area on mammogram, cm2

105

181

304

Absolute dense area on mammogram, cm2

62

76

70

 

Tertiles of percent dense area

Characteristics

1 (< 27.8)

2 (< 49.9)

3 (< 90.4)

Number of controls

330

339

329

Age at mammography, years

48.2

47.4

46.4

Age at menarche, years

12.1

12.5

12.6

Family history of breast cancer, %

6.5

9.2

7.2

Nulliparous at the time of mammography, %

7.1

9.3

12.5

Number of children at mammography1

2.8

2.6

2.4

Age at first birth, years1

25.0

26.2

25.7

Body mass index at mammography, kg/m2

28.5

24.5

22.7

Alcohol use at mammography, g/day

4.1

4.9

5.5

Total area on mammogram, cm2

238

194

156

Absolute dense area on mammogram, cm2

35

75

96

Absolute non-dense area on mammogram, cm2

203

119

59

  1. 1) Among parous women.