Table 1 Distribution of cases and controls by age, study area and selected risk factors of breast cancer
Cases (n = 739) | Controls (n = 815) | ORa | 95 % CI | |||
|---|---|---|---|---|---|---|
N | % | N | % | |||
Study area (département) | ||||||
Côte d'Or | 235 | 31.8 | 284 | 34.8 | ||
Ille-et-Vilaine | 504 | 68.2 | 531 | 65.2 | ||
Age at reference date (years) | ||||||
35-39 | 0 | 0.0 | 1 | 0.1 | ||
40-44 | 1 | 0.1 | 1 | 0.1 | ||
45-49 | 18 | 2.4 | 33 | 4.1 | ||
50-54 | 103 | 13.9 | 109 | 13.4 | ||
55-59 | 189 | 25.6 | 192 | 23.6 | ||
60-64 | 158 | 21.4 | 164 | 20.1 | ||
65-69 | 147 | 19.9 | 192 | 23.6 | ||
70-74 | 123 | 16.6 | 123 | 15.1 | ||
Family history of breast cancer in first degree relatives | ||||||
No | 604 | 81.7 | 715 | 87.7 | 1 | ref |
Yes | 135 | 18.3 | 100 | 12.3 | 1.62 | [1.22-2.16] |
Age at menarche (years) | ||||||
≤ 11 | 131 | 18 | 122 | 15.2 | 1 | ref |
12 | 179 | 24.7 | 172 | 21.4 | 0.98 | [0.71-1.35] |
13 | 155 | 21.3 | 174 | 21.6 | 0.82 | [0.59-1.15] |
14 | 143 | 19.7 | 165 | 20.5 | 0.81 | [0.58-1.13] |
≥ 15 | 118 | 16.3 | 172 | 21.4 | 0.63 | [0.45-0.89] |
Parity | ||||||
Nulliparous | 79 | 10.7 | 50 | 6.1 | 1 | ref |
1 FTPb | 109 | 14.7 | 113 | 13.9 | 0.61 | [0.39-0.95] |
2 FTP | 279 | 37.8 | 270 | 33.1 | 0.65 | [0.44-0.96] |
3 FTP | 183 | 24.8 | 245 | 30.1 | 0.46 | [0.31-0.69] |
≥ 4 FTP | 89 | 12 | 137 | 16.8 | 0.41 | [0.26-0.64] |
Age at first FTP among parous women (years) | ||||||
< 22 | 185 | 28 | 252 | 32.9 | 1 | ref |
22-24 | 196 | 29.7 | 252 | 32.9 | 1.07 | [0.82-1.40] |
25-27 | 141 | 21.4 | 167 | 21.8 | 1.16 | [0.86-1.56] |
> 27 | 138 | 20.9 | 94 | 12.3 | 2.02 | [1.46-2.81] |
Breastfeeding among parous women (weeks) | ||||||
never | 349 | 53.5 | 399 | 52.2 | 1 | ref |
< 26 | 224 | 34.4 | 261 | 34.2 | 1.03 | [0.82-1.31] |
26-52 | 54 | 8.3 | 67 | 8.8 | 0.97 | [0.66-1.43] |
> 52 | 25 | 3.8 | 37 | 4.8 | 0.82 | [0.48-1.40] |
Age at menopause (years)c | ||||||
< 48 | 105 | 22.7 | 115 | 22.9 | 1 | ref |
48-50 | 136 | 29.4 | 157 | 31.2 | 0.85 | [0.59-1.23] |
51-53 | 133 | 28.8 | 126 | 25 | 1.03 | [0.71-1.50] |
≥ 54 | 88 | 19 | 105 | 20.9 | 0.82 | [0.54-1.23] |
Current MHT use | ||||||
No | 589 | 79.7 | 690 | 84.7 | 1 | ref |
Yes | 150 | 20.3 | 125 | 15.3 | 1.44 | [1.10-1.88] |
Height (cm) | ||||||
< 158 | 187 | 25.4 | 230 | 28.2 | 1 | ref |
158-161 | 188 | 25.5 | 198 | 24.3 | 1.25 | [0.94-1.67] |
162-165 | 172 | 23.3 | 223 | 27.4 | 1.03 | [0.77-1.38] |
≥ 166 | 190 | 25.8 | 164 | 20.1 | 1.63 | [1.21-2.20] |
Alcohol consumption (glasses per week) | ||||||
≤ 3 | 542 | 73.3 | 581 | 71.3 | 1 | ref |
4-7 | 108 | 14.6 | 122 | 15.0 | 0.92 | [0.69-1.22] |
8-14 | 53 | 7.2 | 71 | 8.7 | 0.77 | [0.52-1.12] |
> 14 | 36 | 4.9 | 41 | 5.0 | 0.91 | [0.57-1.45] |
Tobacco (pack-years) | ||||||
Never | 500 | 68.3 | 563 | 70.2 | 1 | ref |
< 10 | 119 | 16.3 | 134 | 16.7 | 1.03 | [0.77-1.36] |
≥ 10 | 113 | 15.4 | 105 | 13.1 | 1.28 | [0.95-1.74] |
Physical activity | ||||||
No | 269 | 36.8 | 264 | 32.5 | 1 | ref |
Yes | 462 | 63.2 | 548 | 67.5 | 0.83 | [0.67-1.02] |