Table 6: Hazard ratios (HR) and 95% confidence intervals (CI) from time-dependent covariate analysis of the association of body mass index, waist circumference, and waist-hip ratio with risk of incident, invasive breast cancer in postmenopausal women.

Quintiles P for trend
12345

Average value:
Body mass index
 Age- and energy-adjusted HR (95% CI)1.00
Ref.
1.05
(0.76–1.44)
1.20
(0.89–1.63)
1.18
(0.87–1.61)
1.60
(1.19–2.14)
0.0012
 Multivariable-adjusted HR (95% CI) a1.00
Ref.
1.05
(0.75–1.45)
1.29
(0.94–1.76)
1.25
(0.90–1.71)
1.74
(1.27–2.40)
0.0004
Waist circumference
 Age- and energy-adjusted HR (95% CI)1.00
Ref.
0.89
(0.64–1.22)
0.99
(0.73-1.34)
1.28
(0.96–1.71)
1.56
(1.17–2.07)
<0.0001
 Multivariable-adjusted HR (95% CI)a1.00
Ref.
0.90
(0.65–1.25)
1.02
(0.74–1.40)
1.43
(1.05–1.94)
1.80
(1.32–2.45)
<0.0001
Waist : hip ratio
 Age- and energy-adjusted HR (95% CI)1.00
Ref.
1.24
(0.91–1.69)
1.12
(0.82–1.53)
1.23
(0.91–1.68)
1.48
(1.10–2.00)
0.02
 Multivariable-adjusted HR (95% CI)a1.00
Ref.
1.38
(0.99–1.91)
1.28
(0.92–1.78)
1.46
(1.06–2.03)
1.79
(1.30–2.47)
0.0007

Value 2–4 years prior to diagnosis:
Body mass index
 Age- and energy-adjusted HR (95% CI)1.00
Ref.
0.96
(0.63–1.46)
1.06
(0.71–1.59)
0.97
(0.64–1.47)
1.43
(0.97–2.10)
0.08
 Multivariable-adjusted HR (95% CI)a1.00
Ref.
0.97
(0.63–1.50)
1.16
(0.77–1.77)
1.07
(0.69–1.65)
1.64
(1.08–2.49)
0.02
Waist circumference
 Age- and energy-adjusted HR (95% CI)1.00
Ref.
0.82
(0.51–1.30)
0.61
(0.37–0.99)
0.92
(0.60–1.42)
1.27
(0.84–1.90)
0.17
 Multivariable-adjusted HR (95% CI)a1.00
Ref.
0.88
(0.55–1.41)
0.64
(0.38–1.07)
1.08
(0.69–1.71)
1.53
(0.98–2.37)
0.03
Waist : hip ratio
 Age- and energy-adjusted HR (95% CI)1.00
Ref.
1.15
(0.72–1.84)
0.94
(0.57–1.52)
0.99
(0.62–1.60)
1.38
(0.89–2.14)
0.24
 Multivariable-adjusted HR (95% CI)a1.00
Ref.
1.23
(0.76–2.00)
1.06
(0.64–1.75)
1.14
(0.70–1.88)
1.66
(1.04–2.63)
0.05

Adjusted for age at enrollment, education, ethnicity, family history of breast cancer, age at menarche, age at first full-term birth, parity, age at menopause, oral contraceptive use, duration of hormone therapy, previous breast biopsy, physical activity, alcohol intake, pack-years of smoking, intake of energy, and randomization status.