Table 3 Relative risks (RR) and their 95 % confidence intervals (CI) on the association between alcohol intake and breast cancer risk by body mass index (BMI) in the Swedish Women’s Lifestyle and Health study

Alcohol intake (g/day)

No. of cases

RR (95 % CI)

No. of cases

RR (95 % CI)

p-interaction

Total breast cancer (n = 1,385)

 0

150

1.0

86

0.99 (0.76–1.29)

0.59

 0.1–5

418

1.05 (0.87–1.26)

181

1.00 (0.80–1.24)

 5.1–15

339

1.19 (0.98–1.44)

135

1.08 (0.86–1.37)

  > 15

56

1.32 (0.97–1.81)

20

0.88 (0.55–1.41)

 Per 5 g/day increase

1.03 (1.00–1.05)

0.96 (0.88–1.04)

ER(+)/PR(+) breast cancer (n = 718)

 0

71

1.0

46

1.08 (0.75–1.57)

0.69

 0.1–5

217

1.14 (0.87–1.49)

109

1.23 (0.91–1.66)

 5.1–15

167

1.22 (0.92–1.61)

72

1.18 (0.85–1.65)

  > 15

26

1.28 (0.81–2.03)

10

0.90 (0.46–1.76)

 Per 5 g/day increase

1.03 (0.99–1.06)

0.93 (0.83–1.05)

ER(+)/PR(−) breast cancer (n = 196)

 0

23

1.0

10

0.69 (0.33–1.45)

0.98

 0.1–5

55

0.94 (0.58–1.53)

23

0.77 (0.43–1.39)

 5.1–15

55

1.29 (0.79–2.13)

20

0.98 (0.53–1.81)

  > 15

7

1.06 (0.45–2.50)

3

0.80 (0.24–2.69)

 Per 5 g/day increase

1.02 (0.96–1.09)

0.98 (0.82–1.18)

ER(−)/PR(−) breast cancer (n = 187)

 0

17

1.0

19

1.95 (1.01–3.76)

0.04

 0.1–5

60

1.29 (0.75–2.22)

21

1.01 (0.53–1.93)

 5.1-15

44

1.31 (0.74–2.30)

15

1.03 (0.51–2.08)

  > 15

10

1.96 (0.89–4.34)

1

0.36 (0.05–2.74)

 Per 5 g/day increase

1.02 (0.94–1.11)

0.80 (0.59–1.09)