Table 3 Risk factor associations with epithelial nuclear density among women overall and with adequate stroma (stromal area ≥10%) breast tissue

From: Stroma modifies relationships between risk factor exposure and age-related epithelial involution in benign breast

 

All patients (N = 416)

Adequate stroma (stromal area ≥10%; N = 317)

 

N

Mean (standard error)

Difference (standard error)a

p

N

Mean (standard error)

Difference (standard error)a

p

Age

 <50 years

158

6921.0 (228.3)

Ref

 

127

7702.2 (234.6)

Ref

 

 ≥50 years

258

5958.3 (156.3)

−1056.1 (274.7)

0.0001

190

6660.0 (178.9)

−1137.0 (299.2)

0.0001

Race

 White (ref)

274

6386.7 (163.6)

Ref

 

210

7121.7 (179.5)

Ref

 

 African American

111

6013.4 (245.6)

−579.4 (291.7)

0.05

81

6878.7 (274.3)

−441.5 (322.9)

0.2

 Other

31

6881.3 (510.3)

−82.4 (497.4)

0.9

26

7340.5 (562.2)

−353.5 (519.6)

0.5

Body mass index (kg/m2)

 <25.0 (ref)

156

6921.5 (221.7)

Ref

 

135

7392.7 (225.2)

Ref

 

 25.0–29.9

83

6250.0 (280.9)

−467.1 (352.4)

0.2

64

6935.6 (306.9)

−280.8 (377.5)

0.5

 ≥30.0

177

5831.9 (194.5)

−928.8 (281.8)

0.001

118

6794.0 (239.4)

−440.4 (310.9)

0.2

 Trend test β

  

−67.3 (18.8)

0.0004

  

−38.7 (21.8)

0.08

Mammographic density

 1—Fatty (ref)

34

4489.5 (272.6)

Ref

 

15

5246.0 (503.8)

Ref

 

 2—Scattered fibroglandular

148

5496.2 (195.6)

1061.9 (478.5)

0.03

97

6202.4 (253.1)

1175.9 (671.1)

0.08

 3—Heterogeneously dense

153

7110.9 (229.7)

2379.2 (482.3)

<0.0001

128

7814.1 (225.1)

2353.7 (659.8)

0.0004

 4—Extremely dense

15

6879.2 (653.6)

1860.7 (775.5)

0.02

15

6879.2 (653.6)

1069.1 (877.8)

0.2

 Dense, NOS

33

7405.1 (459.9)

2872.4 (613.0)

<0.0001

32

7530.0 (456.6)

2333.7 (753.9)

0.002

 Missing

33

   

30

   

 Trend test β

  

736.4 (130.0)

<0.0001

  

457.8 (144.6)

0.002

Age at menarche

 <13 years (ref)

202

6260.4 (194.1)

Ref

 

145

7,227.3 (214.7)

Ref

 

 ≥13 years

213

6398.0 (180.0)

322.3 (255.6)

0.2

172

6951.3 (197.2)

−33.6 (281.1)

0.9

 Missing

1

   

0

   

Parity

 Nulliparous (ref)

68

6537.5 (309.5)

Ref

 

55

7153.8 (325.9)

Ref

 

 1–2 births

240

6508.8 (177.4)

303.6 (360.7)

0.4

188

7201.0 (192.8)

475.6 (385.6)

0.2

 ≥3 births

108

5778.5 (249.1)

−241.9 (413.2)

0.6

74

6707.1 (297.0)

121.9 (453.3)

0.8

Age at first term pregnancyb

 <26 years (ref)

206

5955.7 (181.6)

Ref

 

149

6785.6 (209.3)

Ref

 

 ≥26 years

142

6755.9 (236.1)

547.7 (288.1)

0.06

113

7425.4 (252.1)

318.2 (315.1)

0.3

Time since last birthb

 <10 years (ref)

51

7715.8 (426.3)

Ref

 

44

8344.2 (419.3)

Ref

 

 10–19 years

81

6501.6 (308.3)

−786.4 (491.1)

0.1

61

7340.1 (338.1)

−454.7 (520.0)

0.4

 ≥20 years

215

5867.9 (170.3)

−780.0 (581.0)

0.2

157

6593.8 (195.3)

−266.8 (645.8)

0.7

 Missing

1

   

0

   

History of breastfeedingb

 Never (ref)

158

5968.4 (204.5)

Ref

 

113

6789.4 (239.8)

Ref

 

 Ever

190

6543.1 (204.1)

257.9 (288.2)

0.4

149

7267.9 (218.6)

98.6 (320.4)

0.8

Breastfeeding durationb

 <3 months (ref)

208

6076.3 (180.5)

Ref

 

150

6919.0 (208.2)

Ref

 

 ≥3 months

140

6588.1 (241.8)

197.0 (292.0)

0.5

112

7252.5 (256.8)

−54.7 (319.0)

0.9

Oral contraceptive duration

 Never (ref)

69

6120.6 (326.1)

Ref

 

57

6552.7 (363.4)

Ref

 

 ≤10 years

258

6190.6 (164.4)

−290.9 (356.0)

0.4

189

7015.3 (184.8)

116.5 (377.2)

0.8

 >10 years

87

6874.7 (297.9)

341.7 (421.7)

0.4

70

7644.0 (299.6)

686.5 (444.2)

0.1

 Missing

1

   

1

   

Oral contraceptive recency

 Never (ref)

69

6120.6 (326.1)

Ref

 

57

6552.7 (363.4)

Ref

 

 ≤5 years ago

57

7571.8 (367.5)

478.2 (517.7)

0.4

49

8218.7 (345.2)

750.5 (535.5)

0.2

 >5 years ago

288

6120.0 (153.5)

−194.2 (348.6)

0.6

210

6938.7 (173.2)

204.5 (368.6)

0.6

 Missing

2

   

1

   

Menopausal hormone therapy recencyc

 Never (ref)

140

5925.0 (226.3)

Ref

 

106

6579.1 (257.5)

Ref

 

 ≤5 years ago

54

6166.3 (348.3)

323.6 (396.0)

0.4

41

6974.0 (363.9)

336.5 (432.4)

0.4

 >5 years ago

49

5590.0 (311.1)

−38.6 (415.0)

0.9

35

6233.4 (373.0)

48.3 (462.3)

0.9

 Missing

4

   

4

   
  1. aEstimated difference in epithelial nuclear density compared to referent category; adjusted for age and surgery type.
  2. bAmong parous women
  3. cAmong postmenopausal women
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