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Table 3 Invasive breast cancer risk by birthweight and gestation of first-born singleton offspring by oestrogen-receptor statusa

From: Maternal breast cancer risk in relation to birthweight and gestation of her offspring

 

Oestrogen receptor statusa

Positive

Negative

No. of cases

HRb

95% CI

No. of cases

HRb

95% CI

Birthweight (g)

  < 2000

16

1.32

0.80–2.17

2

0.86

0.21–3.49

 2000–2499

58

1.09

0.83–1.42

7

0.70

0.33–1.51

 2500–2999

228

1.06

0.90–1.23

57

1.42

1.03–1.96c

 3000–3499

555

1.00

 

104

1.00

 

 3500–3999

404

0.99

0.87–1.13

81

1.05

0.79–1.41

 4000–4499

95

0.97

0.78–1.21

20

1.07

0.66–1.73

  ≥ 4500

22

1.38

0.89–2.12

6

1.98

0.87–4.51

 Not known

52

1.19

0.89–1.58

8

1.01

0.49–2.07

 p trendd

 

0.43

  

0.09

 

p interaction (trend) = 0.06

Gestation (weeks)

 26–31

19

1.31

0.82–2.08

3

0.97

0.31–3.06

 32–36

123

1.05

0.85–1.29

23

0.95

0.60–1.52

 37–39

377

0.93

0.82–1.06

81

0.91

0.68–1.21

 40–41

543

1.00

 

115

1.00

 

 42–49

199

0.96

0.81–1.15

38

0.84

0.57–1.24

 Not known

169

1.02

0.85–1.22

25

0.76

0.48–1.20

 p trendd

 

0.06

  

0.55

 

p interaction (trend) = 0.82

  1. HR hazard ratio, CI confidence interval
  2. aOestrogen-receptor status of breast cancer
  3. bAdjusted for: attained age (Cox regression time scale); time since recruitment to cohort (0, 1–2, 3+ years); birth cohort (1908–1939, 1940–1949, 1950–1959, 1960–1969, 1970–1996); benign breast disease (yes, no); family history of breast cancer in first-degree relatives (yes, no); socio-economic score (ACORN score as trend, missing); own birthweight (trend, missing); age at menarche (trend, missing); parity (trend); age at first pregnancy (trend); cumulative duration of breast feeding (none, duration trend when reported); current oral contraceptive use before menopause (yes, no); height at age 20 (trend, missing); alcohol consumption (never regular, trend current drinker 1 to < 60 g/day, current drinker 60+ g/day, past drinker, drinker with unknown details); age started smoking (never, < 17, 17–19, 20+, missing); physical activity (log(metabolic equivalent) trend, missing); pre-menopausal body mass index at age 20 years (trend, missing); menopausal status (pre- or post-menopausal), and for those post-menopausal, post-menopausal body mass index (trend, missing), menopausal hormone therapy use (never used, ex-user, current oestrogen-only user, current oestrogen plus progestogen user, current user of other types, missing), and age at menopause (trend, missing)
  4. cp < 0.05
  5. dExcluding not known category
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Breast Cancer Research

ISSN: 1465-542X

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