Table 5.
Hazard ratios (HR) and 95% confidence intervals (CI) from time-dependent covariate analysis of the association of DXA-derived body fat with risk of incident, invasive breast cancer in postmenopausal women.
| Quintiles | P for trend | |||||
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | ||
| Average value: | ||||||
| Whole body fat mass | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.05 (0.76–1.44) |
1.31 (0.97–1.77) |
1.25 (0.92–1.70) |
1.53 (1.13–2.07) |
0.003 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
1.04 (0.75–1.44) |
1.37 (1.00–1.86) |
1.29 (0.93–1.78) |
1.60 (1.16–2.21) |
0.002 |
| Whole body percent fat | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.00 (0.73–1.37) |
1.33 (0.99–1.78) |
1.06 (0.78–1.44) |
1.47 (1.10–1.97) |
0.01 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
0.99 (0.72–1.38) |
1.37 (1.01–1.85) |
1.08 (0.78–1.49) |
1.52 (1.11–2.08) |
0.01 |
| Fat mass of trunk | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.24 (0.90–1.70) |
1.21 (0.89–1.66) |
1.46 (1.07–1.99) |
1.82 (1.34–2.47) |
<0.0001 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
1.33 (0.96–1.85) |
1.29 (0.93–1.79) |
1.64 (1.19–2.27) |
2.07 (1.49–2.87) |
<0.0001 |
| Fat mass of right leg | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.05 (0.77–1.43) |
1.23 (0.91–1.65) |
1.21 (0.90–1.64) |
1.69 (1.27–2.26) |
0.0003 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
0.96 (0.70–1.32) |
1.19 (0.88–1.61) |
1.12 (0.82–1.54) |
1.60 (1.18–2.16) |
0.002 |
| Fat mass of left leg | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.01 (0.74–1.38) |
1.29 (0.96–1.73) |
1.09 (0.81–1.48) |
1.66 (1.25–2.21) |
0.0008 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
0.92 (0.67–1.27) |
1.25 (0.93–1.69) |
1.00 (0.73–1.37) |
1.55 (1.15–2.09) |
0.005 |
| Ratio of trunk fat mass to average of R and L leg fat mass | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.43 (1.06–1.93) |
1.24 (0.91–1.68) |
1.21 (0.89–1.65) |
1.37 (1.01–1.87) |
0.24 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
1.50 (1.10–2.04) |
1.30 (0.94–1.79) |
1.32 (0.95–1.82) |
1.63 (1.18–2.25) |
0.03 |
|
| ||||||
| Value 2–4 years prior to diagnosis: | ||||||
| Whole body fat mass | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.18 (0.80–1.74) |
0.86 (0.56–1.30) |
1.03 (0.69–1.53) |
1.55 (1.06–2.25) |
0.07 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
1.16 (0.78–1.74) |
0.94 (0.61–1.44) |
1.04 (0.68–1.59) |
1.67 (1.12–2.49) |
0.04 |
| Whole body percent fat | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.05 (0.70–1.56) |
1.18 (0.81–1.73) |
0.85 (0.56–1.28) |
1.30 (0.89–1.90) |
0.41 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
1.07 (0.71–1.61) |
1.22 (0.82–1.81) |
0.88 (0.57–1.36) |
1.35 (0.90–2.02) |
0.33 |
| Fat mass of trunk | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.31 (0.88–1.93) |
0.91 (0.60–1.40) |
1.28 (0.86–1.90) |
1.60 (1.08–2.36) |
0.04 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
1.39 (0.93–2.09) |
1.02 (0.66–1.59) |
1.40 (0.92–2.14) |
1.83 (1.21–2.79) |
0.01 |
| Fat mass of right leg | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.19 (0.81–1.76) |
1.11 (0.75–1.65) |
0.91 (0.60–1.39) |
1.56 (1.07–2.26) |
0.12 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
1.11 (0.75–1.66) |
1.08 (0.72–1.61) |
0.85 (0.55–1.32) |
1.50 (1.02–2.22) |
0.17 |
| Fat mass of left leg | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.17 (0.79–1.74) |
1.24 (0.84–1.82) |
0.95 (0.63–1.44) |
1.50 (1.03–2.19) |
0.14 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
1.09 (0.73–1.62) |
1.21 (0.82–1.80) |
0.89 (0.58–1.36) |
1.43 (0.96–2.13) |
0.23 |
| Ratio of trunk fat mass to average of R and L leg fat mass | ||||||
| Age- and energy-adjusted HR (95% CI) | 1.00 Ref. |
1.28 (0.87–1.90) |
1.14 (0.76–1.70) |
1.20 (0.81–1.78) |
1.15 (0.77–1.72) |
0.69 |
| Multivariable-adjusted HR (95% CI)a | 1.00 Ref. |
1.33 (0.89–2.00) |
1.21 (0.79–1.83) |
1.29 (0.85–1.95) |
1.37 (0.90–2.09) |
0.22 |
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.