Q4 (high) | Q3 | Q2 | Q1 (low) | ||||||
---|---|---|---|---|---|---|---|---|---|
N | % | N | % | N | % | N | % | p value | |
Age at entry (years) | |||||||||
<59 | 85 | 39.5 | 67 | 31.5 | 76 | 37.3 | 73 | 34.0 | |
60–64 | 66 | 30.7 | 79 | 37.1 | 60 | 29.4 | 76 | 35.4 | |
65–69 | 46 | 21.4 | 48 | 22.5 | 52 | 25.5 | 49 | 22.9 | |
> =70 | 18 | 8.4 | 19 | 8.9 | 16 | 7.8 | 17 | 7.9 | |
0.75 | |||||||||
Time at entry | |||||||||
< =September 30,1997 | 134 | 62.3 | 125 | 58.7 | 114 | 55.9 | 132 | 61.4 | |
> =October 1, 1997 | 81 | 37.7 | 88 | 41.3 | 90 | 44.1 | 83 | 38.6 | |
0.53 | |||||||||
Date of DNA extraction | |||||||||
Pre-extracted DNA | 69 | 32.1 | 69 | 32.4 | 70 | 34.3 | 90 | 41.9 | |
Newly-extracted DNA | 146 | 67.9 | 144 | 67.6 | 134 | 65.7 | 125 | 58.1 | |
0.12 | |||||||||
Race/ethnicity | |||||||||
White, non-Hispanic | 194 | 90.2 | 197 | 92.5 | 190 | 93.1 | 194 | 90.2 | |
Other | 21 | 9.8 | 16 | 7.5 | 14 | 6.9 | 21 | 9.8 | |
0.60 | |||||||||
Body mass index (kg/m2) | |||||||||
Underweight-normal (15–24.9) | 77 | 35.8 | 84 | 39.4 | 98 | 48.3 | 92 | 43.0 | |
Overweight (25.0 − 29.9) | 91 | 42.3 | 72 | 33.8 | 60 | 29.6 | 70 | 32.7 | |
Obese (> = 30) | 47 | 21.9 | 57 | 26.8 | 45 | 22.2 | 52 | 24.3 | |
0.09 | |||||||||
Age at menarche (years) | |||||||||
<12 | 37 | 17.3 | 44 | 20.7 | 31 | 15.2 | 46 | 21.4 | |
13 | 116 | 54.2 | 122 | 57.3 | 107 | 52.5 | 112 | 52.1 | |
> =14 | 61 | 28.5 | 47 | 22.1 | 66 | 32.5 | 57 | 26.5 | |
0.26 | |||||||||
Number of live births | |||||||||
None | 18 | 8.4 | 20 | 9.4 | 16 | 7.8 | 25 | 11.6 | |
1–2 | 66 | 30.7 | 65 | 30.5 | 66 | 32.4 | 73 | 34.0 | |
> =3 | 131 | 60.9 | 128 | 60.1 | 122 | 59.8 | 117 | 54.4 | |
0.75 | |||||||||
Age at first birth (years) | |||||||||
<20 | 36 | 16.8 | 32 | 15.0 | 24 | 11.8 | 35 | 16.3 | |
20–24 | 101 | 47.2 | 94 | 44.1 | 100 | 49.3 | 95 | 44.2 | |
25–29 | 47 | 22.0 | 54 | 25.4 | 48 | 23.7 | 39 | 18.1 | |
> =30 | 12 | 5.6 | 13 | 6.1 | 15 | 7.4 | 21 | 9.8 | |
Nulliparous | 18 | 8.4 | 20 | 9.4 | 16 | 7.9 | 25 | 11.6 | |
0.56 | |||||||||
Type of menopause | |||||||||
Natural | 129 | 60.0 | 136 | 63.9 | 126 | 61.8 | 145 | 67.4 | |
Bilateral oophorectomy | 20 | 9.3 | 21 | 9.9 | 17 | 8.3 | 20 | 9.3 | |
Other | 66 | 30.7 | 56 | 26.3 | 61 | 29.9 | 50 | 23.3 | |
0.67 | |||||||||
Age at natural menopause (years) | |||||||||
<50 | 53 | 41.1 | 46 | 33.8 | 41 | 32.8 | 46 | 31.7 | |
50–54 | 56 | 43.4 | 69 | 50.7 | 66 | 52.8 | 72 | 49.7 | |
55+ | 20 | 15.5 | 21 | 15.4 | 18 | 14.4 | 27 | 18.6 | |
0.65 | |||||||||
History of benign breast disease | |||||||||
No | 133 | 62.7 | 143 | 69.4 | 130 | 64.4 | 140 | 66.7 | |
Yes | 79 | 37.3 | 63 | 30.6 | 72 | 35.6 | 70 | 33.3 | |
0.51 | |||||||||
Smoking status | |||||||||
Never | 115 | 53.4 | 118 | 55.4 | 115 | 56.4 | 138 | 64.2 | |
Former | 81 | 37.7 | 78 | 36.6 | 72 | 35.3 | 67 | 31.2 | |
Current | 19 | 8.8 | 17 | 8.0 | 17 | 8.3 | 10 | 4.7 | |
0.31 | |||||||||
Recent alcohol intake | |||||||||
No | 45 | 22.6 | 54 | 28.0 | 56 | 29.6 | 56 | 28.0 | |
Yes | 154 | 77.4 | 139 | 72.0 | 133 | 70.4 | 144 | 72.0 | |
Family history of breast cancer | |||||||||
No | 169 | 81.3 | 180 | 86.1 | 168 | 83.2 | 176 | 83.0 | |
Yes | 39 | 18.8 | 29 | 13.9 | 34 | 16.8 | 36 | 17.0 | |
0.60 | |||||||||
Hormone use | |||||||||
Never | 61 | 28.6 | 51 | 23.9 | 55 | 27.1 | 46 | 21.6 | |
Former | 32 | 15.0 | 33 | 15.5 | 24 | 11.8 | 36 | 16.9 | |
Current | 120 | 56.3 | 129 | 60.6 | 124 | 61.1 | 131 | 61.5 | |
0.54 |