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 | P 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 |
aAdjusted 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.