Body Fat and Breast Cancer Risk in Postmenopausal Women: A Longitudinal Study
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
1
2
3
4
5
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) a
1.00 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)a
1.00 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)a
1.00 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)a
1.00 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)a
1.00 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)a
1.00 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.