Skip to main content

Table 4 The association between body mass index and breast cancer risk according to birth year and country

From: Body mass index and breast cancer risk in premenopausal and postmenopausal East Asian women: a pooled analysis of 13 cohort studies

 

n

Body mass index at baseline (kg/m2)

 < 18.5

18.5– < 21

21– < 23

23– < 25

25– < 27.5

27.5– < 30

30-

Trend (per 5 kg/m2)

 

p for interaction

HR (95% CI)

HR (95% CI)

HR

HR (95% CI)

HR (95% CI)

HR (95% CI)

HR (95% CI)

HR (95% CI)

p

Birth year

Premenopausal women at baseline

           

  Breast cancer that developed before 50 years of age

           

   1944 or before

32,654

1.03 (0.29–3.66)

1.35 (0.66–2.76)

1 (ref.)

1.22 (0.57–2.60)

1.96 (0.92–4.19)

0.43 (0.06–3.31)

4.53 (1.47–13.96)

1.25 (0.85–1.84)

0.27

0.69

   1945–1952

39,693

0.88 (0.44–1.76)

0.99 (0.69–1.42)

1 (ref.)

0.84 (0.57–1.23)

1.16 (0.77–1.75)

1.13 (0.62–2.05)

1.18 (0.51–2.73)

1.12 (0.90–1.38)

0.32

 

   1953 or after

34,446

0.82 (0.44–1.51)

1.23 (0.91–1.67)

1 (ref.)

1.07 (0.77–1.49)

1.11 (0.76–1.62)

0.85 (0.46–1.56)

0.75 (0.30–1.86)

0.92 (0.76–1.12)

0.40

 

  Breast cancer that developed after 50 years of age

           

   1944 or before

38,518

0.85 (0.58–1.24)

0.94 (0.74–1.20)

1 (ref.)

1.03 (0.81–1.31)

1.26 (0.97–1.64)

1.33 (0.93–1.90)

1.18 (0.69–2.01)

1.15 (1.02–1.30)

0.03

0.98

   1945–1952

41,962

1.02 (0.65–1.60)

0.81 (0.63–1.05)

1 (ref.)

1.10 (0.88–1.36)

1.11 (0.88–1.41)

1.09 (0.79–1.51)

1.05 (0.67–1.64)

1.10 (0.97–1.24)

0.13

 

   1953 or after

30,060

0.74 (0.40–1.38)

0.92 (0.68–1.23)

1 (ref.)

0.94 (0.70–1.24)

1.03 (0.75–1.41)

0.99 (0.63–1.57)

0.98 (0.49–1.93)

1.08 (0.91–1.28)

0.39

 

Postmenopausal women at baseline

           

   1928 or earlier

68,886

0.66 (0.48–0.92)

0.68 (0.53–0.87)

1 (ref.)

1.17 (0.94–1.46)

1.23 (0.97–1.55)

1.69 (1.27–2.24)

1.81(1.24-.62)

1.44(1.31–1.58)

 < 0.001

0.24

   1929–1936

71,600

0.99 (0.67–1.46)

0.79 (0.62–1.01)

1 (ref.)

1.32 (1.10–1.59)

1.26 (1.04–1.53)

1.23 (0.96–1.56)

1.45 (1.07-

1.23 (1.12–1.35)

 < 0.001

 

   1937 or later

59,917

0.80 (0.51–1.27)

1.17 (0.93–1.46)

1 (ref.)

1.31 (1.08–1.59)

1.42 (1.16–1.73)

1.55 (1.21–1.99)

2.03 (1.52–2.72)

1.30 (1.19–1.43)

 < 0.001

 

Country

 Premenopausal women at baseline

           

  Breast cancer that developed before 50 years of age

           

   Japan

63,588

0.86 (0.48–1.55)

1.10 (0.81–1.50)

1 (ref.)

0.97 (0.70–1.35)

1.36 (0.95–1.94)

1.08 (0.61–1.91)

1.81 (0.94–3.49)

1.17 (0.97–1.41)

0.09

0.04

   Korea

10,229

1.14 (0.46–2.80)

1.43 (0.85–2.39)

1 (ref.)

1.04 (0.57–1.88)

0.78 (0.36–1.67)

0.21 (0.03–1.58)

0.74 (0.17–3.13)

0.63 (0.43–0.92)

0.02

 

   China

32,976

0.67 (0.27–1.69)

1.09 (0.73–1.63)

1 (ref.)

0.95 (0.63–1.42)

1.16 (0.75–1.80)

1.01 (0.53–1.94)

0.67 (0.21–2.13)

1.02 (0.80–1.29)

0.88

 

  Breast cancer that developed after 50 years of age

           

   Japan

67,282

0.96 (0.70–1.32)

0.93 (0.76–1.12)

1 (ref.)

1.12 (0.92–1.35)

1.19 (0.96–1.47)

1.45 (1.10–1.92)

1.19 (0.77–1.83)

1.16 (1.05–1.28)

0.005

0.82

   Korea

6794

0.61 (0.08–4.60)

0.63 (0.28–1.45)

1 (ref.)

0.92 (0.46–1.83)

0.61 (0.25–1.47)

0.45 (0.10–1.99)

0.40 (0.05–3.05)

0.86 (0.53–1.39)

0.53

 

   China

36,464

0.77 (0.47–1.27)

0.89 (0.70–1.13)

1 (ref.)

0.96 (0.77–1.19)

1.13 (0.90–1.42)

0.90 (0.64–1.26)

1.04 (0.66–1.62)

1.08 (0.95–1.22)

0.25

 

Postmenopausal women at baseline

           

   Japan

141,822

0.74 (0.57–0.94)

0.76 (0.64–0.90)

1 (ref.)

1.27 (1.11–1.45)

1.22 (1.05–1.41)

1.42 (1.18–1.71)

1.45 (1.11–1.88)

1.33 (1.24–1.42)

 < 0.001

0.15

   Korea

22,050

0.59 (0.14–2.45)

1.43 (0.89–2.31)

1 (ref.)

1.30 (0.85–1.99)

0.98 (0.60–1.59)

1.10 (0.58–2.09)

1.95 (0.96–3.94)

1.05 (0.82–1.34)

0.70

 

   China

36,531

1.11 (0.69–1.80)

1.12 (0.83–1.51)

1 (ref.)

1.31 (1.03–1.67)

1.60 (1.27–2.03)

1.61 (1.23–2.12)

2.17 (1.61–2.92)

1.33 (1.21–1.47)

 < 0.001

 
  1. HR hazard ratio, CI confident interval
  2. Estimated hazard ratio after adjustments for age at enrollment (continuous), study (13 cohorts), smoking status (never, former, current smokers), alcohol consumption (non-drinkers or current drinkers), age at menarche (≤ 10 y, 11–12 y, 13–14 y, 15–16 y, ≥ 17 y), nulliparity (yes, no), age at first delivery (≤ 20 y, 21–25 y, 26–30 y, ≥ 31 y), and age at menopause (≤ 44 y, 45–49 y, 50–54 y, ≥ 55 y)(postmenopausal women only)
Back to article page

Breast Cancer Research

ISSN: 1465-542X

Contact us