Body Fat and Breast Cancer Risk in Postmenopausal Women: A Longitudinal Study
Table 4
Hazard ratios (HR) and 95% confidence intervals (CI) for the association of body mass index, waist circumference, and waist-hip ratio with risk of incident, invasive breast cancer in postmenopausal women.
Quintiles
for trend
1
2
3
4
5
Body mass index
Cases
80
89
102
102
129
Person-years
25,409
25,468
25,058
24,868
24,109
Age- and energy-adjusted HR (95% CI)
1.00 Ref.
1.13 (0.83–1.53)
1.31 (0.98–1.76)
1.33 (0.99–1.79)
1.74 (1.31–2.31)
<0.0001
Multivariable-adjusted HR (95% CI)a
1.00 Ref.
1.15 (0.84–1.57)
1.41 (1.04–1.91)
1.43 (1.05–1.95)
1.97 (1.45–2.68)
<0.0001
Waist circumference
Cases
89
74
100
108
131
Person-years
27,187
23,190
25,014
25,401
24,332
Age- and energy-adjusted HR (95% CI)
1.00 Ref.
0.98 (0.72–1.43)
1.22 (0.91–1.63)
1.30 (0.98–1.72)
1.68 (1.28–2.21)
<0.0001
Multivariable-adjusted HR (95% CI)a
1.00 Ref.
1.00 (0.72–1.37)
1.27 (0.94–1.72)
1.44 (1.07–1.94)
1.97 (1.46–2.65)
<0.0001
Waist : hip ratio
Cases
85
103
102
88
124
Person-years
26,315
25,472
25,139
24,480
23,655
Age- and energy-adjusted HR (95% CI)
1.00 Ref.
1.26 (0.95–1.69)
1.26 (0.94–1.68)
1.12 (0.83–1.51)
1.61 (1.22–2.13)
0.004
Multivariable-adjusted HR (95% CI)a
1.00 Ref.
1.39 (1.02–1.87)
1.46 (1.08–1.98)
1.30 (0.94–1.78)
1.91 (1.41–2.58)
0.0001
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.
