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Table 1 Distribution of cases and controls by age, study area and selected risk factors of breast cancer

From: Weight and weight changes throughout life and postmenopausal breast cancer risk: a case-control study in France

  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]
  1. aOdds ratios adjusted for age at reference date and study area
  2. bFTP: Full-Term Pregnancy
  3. cAge at menopause unknown in 227 cases and 312 controls