Table 2.
Relationship between measures of body size at baseline and risk of ER+ and triple-negative breast cancer
| Non-cases | Cases* |
|||||
|---|---|---|---|---|---|---|
| ER+ | Triple-negative | |||||
| n (%) | n (%) | HR (95% CI)† | n (%) | HR (95% CI)† | p-value‡ | |
| BMI(kg/m2) | ||||||
| Quartiles | ||||||
| <23.75 | 37,377 (25) | 596 (23) | 1.0 (ref) | 66 (22) | 1.0 (ref) | 0.28 |
| 23.75 – 26.89 | 37,318 (25) | 650 (25) | 1.19 (1.05–1.35) | 71 (23) | 0.99 (0.67–1.46) | |
| 26.90 – 31.04 | 37,326 (25) | 648 (25) | 1.17 (1.03–1.33) | 80 (26) | 1.21 (0.83–1.77) | |
| >31.05 | 37,207 (25) | 698 (27) | 1.39 (1.22–1.58) | 89 (29) | 1.35 (0.92–1.99) | |
| Missing | 1,301 | 18 | 1 | |||
| ptrend | <0.01 | 0.07 | ||||
| Standard Cutpoints | ||||||
| <25.0 | 53,107 (35) | 845 (33) | 1.0 (ref) | 96 (31) | 1.0 (ref) | 0.36 |
| 25.0 – 29.9 | 52,676 (35) | 889 (34) | 1.14 (1.02–1.26) | 103 (34) | 1.16 (0.84–1.61) | |
| ≥30.0 | 45,700 (30) | 858 (33) | 1.35 (1.20–1.51) | 107 (35) | 1.37 (0.98–1.93) | |
| Missing | 1,301 | 18 | 1 | |||
| ptrend | <0.01 | 0.06 | ||||
| Waist-to-hip ratio (WHR)§ | ||||||
| <0.758 | 37,507 (25) | 633 (24) | 1.0 (ref) | 75 (24) | 1.0 (ref) | 0.36 |
| 0.758 – 0.804 | 37,472 (25) | 621 (24) | 0.93 (0.82–1.05) | 84 (27) | 1.13 (0.79–1.62) | |
| 0.805 – 0.856 | 37,629 (25) | 663 (25) | 1.04 (0.91–1.18) | 73 (24) | 0.99 (0.68–1.46) | |
| ≥0.857 | 37,220 (25) | 689 (26) | 1.06 (0.93–1.21) | 75 (24) | 0.99 (0.66–1.49) | |
| Missing | 701 | 4 | 0 | |||
| ptrend | 0.21 | 0.82 | ||||
| Waist circumference (cm)§ | ||||||
| <76 | 37,786 (25) | 574 (22) | 1.0 (ref) | 82 (27) | 1.0 (ref) | 0.07 |
| 76 – 84.4 | 37,537 (25) | 663 (25) | 1.14 (0.99–1.31) | 58 (19) | 0.61 (0.40–1.95) | |
| 84.5 – 94.5 | 38,596 (26) | 671 (26) | 1.14 (0.96–1.35) | 83 (27) | 0.66 (0.40–1.08) | |
| ≥95 | 36,061 (24) | 699 (27) | 1.34 (1.09–1.64) | 84 (27) | 0.66 (0.37–1.20) | |
| Missing | 549 | 3 | 0 | |||
| ptrend | 0.01 | 0.23 | ||||
| Hip circumference (cm)§ | ||||||
| <98 | 38,707 (26) | 574 (22) | 1.0 (ref) | 71 (23) | 1.0 (ref) | 0.31 |
| 98 – 104.4 | 37,141 (25) | 646 (25) | 1.19 (1.03–1.37) | 68 (22) | 0.87 (0.56–1.33) | |
| 104.5 – 112.9 | 38,611 (26) | 712 (27) | 1.27 (1.08–1.51) | 85 (28) | 0.87 (0.52–1.43) | |
| ≥113 | 35,442 (24) | 675 (26) | 1.28 (1.03–1.58) | 83 (27) | 0.81 (0.44–1.50) | |
| Missing | 628 | 3 | 0 | |||
| ptrend | 0.01 | 0.54 | ||||
*
ER+ = estrogen receptor-positive cases with known HER2 expression status; triple-negative = ER−/PR−/HER2−
†
Adjusted for age, education, income, family history of breast cancer, race, and recreational physical activity level, history of mammography (at baseline), and mammography during follow-up.
‡
Analysis of the partial likelihoods for equality between subtype-specific estimates.
§
Additionally adjusted for BMI at baseline.