From: Maternal breast cancer risk in relation to birthweight and gestation of her offspring
Risk factor | Pre-menopausala | Post-menopausala | Breast cancer overall | ||||||
---|---|---|---|---|---|---|---|---|---|
No. of cases | HRb | 95% CI | No. of cases | HRb | 95% CI | No. of cases | HRb | 95% CI | |
Birthweight (g) | |||||||||
  < 2000 | 8 | 2.05 | 1.01–4.17c | 10 | 0.91 | 0.48-1.70 | 18 | 1.21 | 0.76–1.94 |
 2000–2499 | 11 | 0.78 | 0.42–1.43 | 56 | 1.10 | 0.83–1.45 | 67 | 1.03 | 0.80–1.33 |
 2500–2999 | 62 | 1.06 | 0.79–1.42 | 231 | 1.13 | 0.97–1.32 | 293 | 1.12 | 0.97–1.28 |
 3000–3499 | 162 | 1.00 |  | 514 | 1.00 |  | 676 | 1.00 |  |
 3500–3999 | 141 | 1.10 | 0.88–1.38 | 360 | 0.98 | 0.85–1.12 | 501 | 1.01 | 0.90–1.13 |
 4000–4499 | 35 | 1.01 | 0.70–1.46 | 86 | 1.01 | 0.80–1.27 | 121 | 1.01 | 0.83–1.22 |
  ≥ 4500 | 10 | 1.73 | 0.91–3.28 | 20 | 1.46 | 0.93–2.28 | 30 | 1.53 | 1.06–2.21c |
 Not known | 20 | 1.76 | 1.11–2.81c | 41 | 0.98 | 0.71–1.35 | 61 | 1.14 | 0.88–1.49 |
 p trendd |  | 0.55 |  |  | 0.50 |  |  | 0.86 |  |
p interaction (trend) = 0.39 | |||||||||
Gestation (weeks) | |||||||||
 26–31 | 10 | 2.38 | 1.26–4.49e | 12 | 0.95 | 0.53–1.68 | 22 | 1.30 | 0.85–1.99 |
 32–36 | 33 | 1.23 | 0.85–1.78 | 117 | 1.09 | 0.89–1.33 | 150 | 1.10 | 0.92–1.32 |
 37–39 | 116 | 0.92 | 0.73–1.15 | 355 | 1.14 | 0.99–1.30 | 471 | 1.07 | 0.95–1.21 |
 40–41 | 200 | 1.00 |  | 481 | 1.00 |  | 681 | 1.00 |  |
  ≥ 42 | 70 | 0.93 | 0.71–1.22 | 175 | 1.06 | 0.89–1.26 | 245 | 1.02 | 0.88–1.18 |
 Not known | 20 | 0.83 | 0.53–1.32 | 178 | 1.09 | 0.91–1.30 | 198 | 1.04 | 0.88–1.22 |
 p trendd |  | 0.03 |  |  | 0.28 |  |  | 0.05 |  |
p interaction (trend) = 0.21 |